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// Google Mock - a framework for writing C++ mock classes.
//
// This file tests some commonly used argument matchers.

// Silence warning C4244: 'initializing': conversion from 'int' to 'short',
// possible loss of data and C4100, unreferenced local parameter
#ifdef _MSC_VER
                                                                                                                        # pragma warning(push)
# pragma warning(disable:4244)
# pragma warning(disable:4100)
#endif

#include "gmock/gmock-matchers.h"
#include "gmock/gmock-more-matchers.h"

#include <string.h>
#include <time.h>
#include <deque>
#include <forward_list>
#include <functional>
#include <iostream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <sstream>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "gtest/gtest-spi.h"

namespace testing {
    namespace gmock_matchers_test {
        namespace {

            using std::greater;
            using std::less;
            using std::list;
            using std::make_pair;
            using std::map;
            using std::multimap;
            using std::multiset;
            using std::ostream;
            using std::pair;
            using std::set;
            using std::stringstream;
            using std::vector;
            using testing::internal::DummyMatchResultListener;
            using testing::internal::ElementMatcherPair;
            using testing::internal::ElementMatcherPairs;
            using testing::internal::ExplainMatchFailureTupleTo;
            using testing::internal::FloatingEqMatcher;
            using testing::internal::FormatMatcherDescription;
            using testing::internal::IsReadableTypeName;
            using testing::internal::MatchMatrix;
            using testing::internal::PredicateFormatterFromMatcher;
            using testing::internal::RE;
            using testing::internal::StreamMatchResultListener;
            using testing::internal::Strings;

// Helper for testing container-valued matchers in mock method context. It is
// important to test matchers in this context, since it requires additional type
// deduction beyond what EXPECT_THAT does, thus making it more restrictive.
            struct ContainerHelper {
                MOCK_METHOD1(Call, void(std::vector<std::unique_ptr<int>>));
            };

            std::vector<std::unique_ptr<int>> MakeUniquePtrs(const std::vector<int> &ints) {
                std::vector<std::unique_ptr<int>> pointers;
                for (int i: ints) pointers.emplace_back(new int(i));
                return pointers;
            }

// For testing ExplainMatchResultTo().
            class GreaterThanMatcher : public MatcherInterface<int> {
            public:
                explicit GreaterThanMatcher(int rhs) : rhs_(rhs) {}

                void DescribeTo(ostream *os) const override { *os << "is > " << rhs_; }

                bool MatchAndExplain(int lhs, MatchResultListener *listener) const override {
                    const int diff = lhs - rhs_;
                    if (diff > 0) {
                        *listener << "which is " << diff << " more than " << rhs_;
                    } else if (diff == 0) {
                        *listener << "which is the same as " << rhs_;
                    } else {
                        *listener << "which is " << -diff << " less than " << rhs_;
                    }

                    return lhs > rhs_;
                }

            private:
                int rhs_;
            };

            Matcher<int> GreaterThan(int n) {
                return MakeMatcher(new GreaterThanMatcher(n));
            }

            std::string OfType(const std::string &type_name) {
#if GTEST_HAS_RTTI
                return " (of type " + type_name + ")";
#else
                return "";
#endif
            }

// Returns the description of the given matcher.
            template<typename T>
            std::string Describe(const Matcher<T> &m) {
                return DescribeMatcher<T>(m);
            }

// Returns the description of the negation of the given matcher.
            template<typename T>
            std::string DescribeNegation(const Matcher<T> &m) {
                return DescribeMatcher<T>(m, true);
            }

// Returns the reason why x matches, or doesn't match, m.
            template<typename MatcherType, typename Value>
            std::string Explain(const MatcherType &m, const Value &x) {
                StringMatchResultListener listener;
                ExplainMatchResult(m, x, &listener);
                return listener.str();
            }

            TEST(MonotonicMatcherTest, IsPrintable) {
                stringstream ss;
                ss << GreaterThan(5);
                EXPECT_EQ("is > 5", ss.str());
            }

            TEST(MatchResultListenerTest, StreamingWorks) {
                StringMatchResultListener listener;
                listener << "hi" << 5;
                EXPECT_EQ("hi5", listener.str());

                listener.Clear();
                EXPECT_EQ("", listener.str());

                listener << 42;
                EXPECT_EQ("42", listener.str());

                // Streaming shouldn't crash when the underlying ostream is NULL.
                DummyMatchResultListener dummy;
                dummy << "hi" << 5;
            }

            TEST(MatchResultListenerTest, CanAccessUnderlyingStream) {
                EXPECT_TRUE(DummyMatchResultListener().stream() == nullptr);
                EXPECT_TRUE(StreamMatchResultListener(nullptr).stream() == nullptr);

                EXPECT_EQ(&std::cout, StreamMatchResultListener(&std::cout).stream());
            }

            TEST(MatchResultListenerTest, IsInterestedWorks) {
                EXPECT_TRUE(StringMatchResultListener().IsInterested());
                EXPECT_TRUE(StreamMatchResultListener(&std::cout).IsInterested());

                EXPECT_FALSE(DummyMatchResultListener().IsInterested());
                EXPECT_FALSE(StreamMatchResultListener(nullptr).IsInterested());
            }

// Makes sure that the MatcherInterface<T> interface doesn't
// change.
            class EvenMatcherImpl : public MatcherInterface<int> {
            public:
                bool MatchAndExplain(int x,
                                     MatchResultListener * /* listener */) const override {
                    return x % 2 == 0;
                }

                void DescribeTo(ostream *os) const override { *os << "is an even number"; }

                // We deliberately don't define DescribeNegationTo() and
                // ExplainMatchResultTo() here, to make sure the definition of these
                // two methods is optional.
            };

// Makes sure that the MatcherInterface API doesn't change.
            TEST(MatcherInterfaceTest, CanBeImplementedUsingPublishedAPI) {
                EvenMatcherImpl m;
            }

// Tests implementing a monomorphic matcher using MatchAndExplain().

            class NewEvenMatcherImpl : public MatcherInterface<int> {
            public:
                bool MatchAndExplain(int x, MatchResultListener *listener) const override {
                    const bool match = x % 2 == 0;
                    // Verifies that we can stream to a listener directly.
                    *listener << "value % " << 2;
                    if (listener->stream() != nullptr) {
                        // Verifies that we can stream to a listener's underlying stream
                        // too.
                        *listener->stream() << " == " << (x % 2);
                    }
                    return match;
                }

                void DescribeTo(ostream *os) const override { *os << "is an even number"; }
            };

            TEST(MatcherInterfaceTest, CanBeImplementedUsingNewAPI) {
                Matcher<int> m = MakeMatcher(new NewEvenMatcherImpl);
                EXPECT_TRUE(m.Matches(2));
                EXPECT_FALSE(m.Matches(3));
                EXPECT_EQ("value % 2 == 0", Explain(m, 2));
                EXPECT_EQ("value % 2 == 1", Explain(m, 3));
            }

// Tests default-constructing a matcher.
            TEST(MatcherTest, CanBeDefaultConstructed) {
                Matcher<double> m;
            }

// Tests that Matcher<T> can be constructed from a MatcherInterface<T>*.
            TEST(MatcherTest, CanBeConstructedFromMatcherInterface) {
                const MatcherInterface<int> *impl = new EvenMatcherImpl;
                Matcher<int> m(impl);
                EXPECT_TRUE(m.Matches(4));
                EXPECT_FALSE(m.Matches(5));
            }

// Tests that value can be used in place of Eq(value).
            TEST(MatcherTest, CanBeImplicitlyConstructedFromValue) {
                Matcher<int> m1 = 5;
                EXPECT_TRUE(m1.Matches(5));
                EXPECT_FALSE(m1.Matches(6));
            }

// Tests that NULL can be used in place of Eq(NULL).
            TEST(MatcherTest, CanBeImplicitlyConstructedFromNULL) {
                Matcher<int *> m1 = nullptr;
                EXPECT_TRUE(m1.Matches(nullptr));
                int n = 0;
                EXPECT_FALSE(m1.Matches(&n));
            }

// Tests that matchers can be constructed from a variable that is not properly
// defined. This should be illegal, but many users rely on this accidentally.
            struct Undefined {
                virtual ~Undefined() = 0;

                static const int kInt = 1;
            };

            TEST(MatcherTest, CanBeConstructedFromUndefinedVariable) {
                Matcher<int> m1 = Undefined::kInt;
                EXPECT_TRUE(m1.Matches(1));
                EXPECT_FALSE(m1.Matches(2));
            }

// Test that a matcher parameterized with an abstract class compiles.
            TEST(MatcherTest, CanAcceptAbstractClass) { Matcher<const Undefined &> m = _; }

// Tests that matchers are copyable.
            TEST(MatcherTest, IsCopyable) {
                // Tests the copy constructor.
                Matcher<bool> m1 = Eq(false);
                EXPECT_TRUE(m1.Matches(false));
                EXPECT_FALSE(m1.Matches(true));

                // Tests the assignment operator.
                m1 = Eq(true);
                EXPECT_TRUE(m1.Matches(true));
                EXPECT_FALSE(m1.Matches(false));
            }

// Tests that Matcher<T>::DescribeTo() calls
// MatcherInterface<T>::DescribeTo().
            TEST(MatcherTest, CanDescribeItself) {
                EXPECT_EQ("is an even number",
                          Describe(Matcher<int>(new EvenMatcherImpl)));
            }

// Tests Matcher<T>::MatchAndExplain().
            TEST(MatcherTest, MatchAndExplain) {
                Matcher<int> m = GreaterThan(0);
                StringMatchResultListener listener1;
                EXPECT_TRUE(m.MatchAndExplain(42, &listener1));
                EXPECT_EQ("which is 42 more than 0", listener1.str());

                StringMatchResultListener listener2;
                EXPECT_FALSE(m.MatchAndExplain(-9, &listener2));
                EXPECT_EQ("which is 9 less than 0", listener2.str());
            }

// Tests that a C-string literal can be implicitly converted to a
// Matcher<std::string> or Matcher<const std::string&>.
            TEST(StringMatcherTest, CanBeImplicitlyConstructedFromCStringLiteral) {
                Matcher<std::string> m1 = "hi";
                EXPECT_TRUE(m1.Matches("hi"));
                EXPECT_FALSE(m1.Matches("hello"));

                Matcher<const std::string &> m2 = "hi";
                EXPECT_TRUE(m2.Matches("hi"));
                EXPECT_FALSE(m2.Matches("hello"));
            }

// Tests that a string object can be implicitly converted to a
// Matcher<std::string> or Matcher<const std::string&>.
            TEST(StringMatcherTest, CanBeImplicitlyConstructedFromString) {
                Matcher<std::string> m1 = std::string("hi");
                EXPECT_TRUE(m1.Matches("hi"));
                EXPECT_FALSE(m1.Matches("hello"));

                Matcher<const std::string &> m2 = std::string("hi");
                EXPECT_TRUE(m2.Matches("hi"));
                EXPECT_FALSE(m2.Matches("hello"));
            }

#if GTEST_HAS_ABSL
                                                                                                                                    // Tests that a C-string literal can be implicitly converted to a
// Matcher<absl::string_view> or Matcher<const absl::string_view&>.
TEST(StringViewMatcherTest, CanBeImplicitlyConstructedFromCStringLiteral) {
  Matcher<absl::string_view> m1 = "cats";
  EXPECT_TRUE(m1.Matches("cats"));
  EXPECT_FALSE(m1.Matches("dogs"));

  Matcher<const absl::string_view&> m2 = "cats";
  EXPECT_TRUE(m2.Matches("cats"));
  EXPECT_FALSE(m2.Matches("dogs"));
}

// Tests that a std::string object can be implicitly converted to a
// Matcher<absl::string_view> or Matcher<const absl::string_view&>.
TEST(StringViewMatcherTest, CanBeImplicitlyConstructedFromString) {
  Matcher<absl::string_view> m1 = std::string("cats");
  EXPECT_TRUE(m1.Matches("cats"));
  EXPECT_FALSE(m1.Matches("dogs"));

  Matcher<const absl::string_view&> m2 = std::string("cats");
  EXPECT_TRUE(m2.Matches("cats"));
  EXPECT_FALSE(m2.Matches("dogs"));
}

// Tests that a absl::string_view object can be implicitly converted to a
// Matcher<absl::string_view> or Matcher<const absl::string_view&>.
TEST(StringViewMatcherTest, CanBeImplicitlyConstructedFromStringView) {
  Matcher<absl::string_view> m1 = absl::string_view("cats");
  EXPECT_TRUE(m1.Matches("cats"));
  EXPECT_FALSE(m1.Matches("dogs"));

  Matcher<const absl::string_view&> m2 = absl::string_view("cats");
  EXPECT_TRUE(m2.Matches("cats"));
  EXPECT_FALSE(m2.Matches("dogs"));
}
#endif  // GTEST_HAS_ABSL

// Tests that a std::reference_wrapper<std::string> object can be implicitly
// converted to a Matcher<std::string> or Matcher<const std::string&> via Eq().
            TEST(StringMatcherTest,
                 CanBeImplicitlyConstructedFromEqReferenceWrapperString) {
                std::string value = "cats";
                Matcher<std::string> m1 = Eq(std::ref(value));
                EXPECT_TRUE(m1.Matches("cats"));
                EXPECT_FALSE(m1.Matches("dogs"));

                Matcher<const std::string &> m2 = Eq(std::ref(value));
                EXPECT_TRUE(m2.Matches("cats"));
                EXPECT_FALSE(m2.Matches("dogs"));
            }

// Tests that MakeMatcher() constructs a Matcher<T> from a
// MatcherInterface* without requiring the user to explicitly
// write the type.
            TEST(MakeMatcherTest, ConstructsMatcherFromMatcherInterface) {
                const MatcherInterface<int> *dummy_impl = nullptr;
                Matcher<int> m = MakeMatcher(dummy_impl);
            }

// Tests that MakePolymorphicMatcher() can construct a polymorphic
// matcher from its implementation using the old API.
            const int g_bar = 1;

            class ReferencesBarOrIsZeroImpl {
            public:
                template<typename T>
                bool MatchAndExplain(const T &x,
                                     MatchResultListener * /* listener */) const {
                    const void *p = &x;
                    return p == &g_bar || x == 0;
                }

                void DescribeTo(ostream *os) const { *os << "g_bar or zero"; }

                void DescribeNegationTo(ostream *os) const {
                    *os << "doesn't reference g_bar and is not zero";
                }
            };

// This function verifies that MakePolymorphicMatcher() returns a
// PolymorphicMatcher<T> where T is the argument's type.
            PolymorphicMatcher<ReferencesBarOrIsZeroImpl> ReferencesBarOrIsZero() {
                return MakePolymorphicMatcher(ReferencesBarOrIsZeroImpl());
            }

            TEST(MakePolymorphicMatcherTest, ConstructsMatcherUsingOldAPI) {
                // Using a polymorphic matcher to match a reference type.
                Matcher<const int &> m1 = ReferencesBarOrIsZero();
                EXPECT_TRUE(m1.Matches(0));
                // Verifies that the identity of a by-reference argument is preserved.
                EXPECT_TRUE(m1.Matches(g_bar));
                EXPECT_FALSE(m1.Matches(1));
                EXPECT_EQ("g_bar or zero", Describe(m1));

                // Using a polymorphic matcher to match a value type.
                Matcher<double> m2 = ReferencesBarOrIsZero();
                EXPECT_TRUE(m2.Matches(0.0));
                EXPECT_FALSE(m2.Matches(0.1));
                EXPECT_EQ("g_bar or zero", Describe(m2));
            }

// Tests implementing a polymorphic matcher using MatchAndExplain().

            class PolymorphicIsEvenImpl {
            public:
                void DescribeTo(ostream *os) const { *os << "is even"; }

                void DescribeNegationTo(ostream *os) const {
                    *os << "is odd";
                }

                template<typename T>
                bool MatchAndExplain(const T &x, MatchResultListener *listener) const {
                    // Verifies that we can stream to the listener directly.
                    *listener << "% " << 2;
                    if (listener->stream() != nullptr) {
                        // Verifies that we can stream to the listener's underlying stream
                        // too.
                        *listener->stream() << " == " << (x % 2);
                    }
                    return (x % 2) == 0;
                }
            };

            PolymorphicMatcher<PolymorphicIsEvenImpl> PolymorphicIsEven() {
                return MakePolymorphicMatcher(PolymorphicIsEvenImpl());
            }

            TEST(MakePolymorphicMatcherTest, ConstructsMatcherUsingNewAPI) {
                // Using PolymorphicIsEven() as a Matcher<int>.
                const Matcher<int> m1 = PolymorphicIsEven();
                EXPECT_TRUE(m1.Matches(42));
                EXPECT_FALSE(m1.Matches(43));
                EXPECT_EQ("is even", Describe(m1));

                const Matcher<int> not_m1 = Not(m1);
                EXPECT_EQ("is odd", Describe(not_m1));

                EXPECT_EQ("% 2 == 0", Explain(m1, 42));

                // Using PolymorphicIsEven() as a Matcher<char>.
                const Matcher<char> m2 = PolymorphicIsEven();
                EXPECT_TRUE(m2.Matches('\x42'));
                EXPECT_FALSE(m2.Matches('\x43'));
                EXPECT_EQ("is even", Describe(m2));

                const Matcher<char> not_m2 = Not(m2);
                EXPECT_EQ("is odd", Describe(not_m2));

                EXPECT_EQ("% 2 == 0", Explain(m2, '\x42'));
            }

// Tests that MatcherCast<T>(m) works when m is a polymorphic matcher.
            TEST(MatcherCastTest, FromPolymorphicMatcher) {
                Matcher<int> m = MatcherCast<int>(Eq(5));
                EXPECT_TRUE(m.Matches(5));
                EXPECT_FALSE(m.Matches(6));
            }

// For testing casting matchers between compatible types.
            class IntValue {
            public:
                // An int can be statically (although not implicitly) cast to a
                // IntValue.
                explicit IntValue(int a_value) : value_(a_value) {}

                int value() const { return value_; }

            private:
                int value_;
            };

// For testing casting matchers between compatible types.
            bool IsPositiveIntValue(const IntValue &foo) {
                return foo.value() > 0;
            }

// Tests that MatcherCast<T>(m) works when m is a Matcher<U> where T
// can be statically converted to U.
            TEST(MatcherCastTest, FromCompatibleType) {
                Matcher<double> m1 = Eq(2.0);
                Matcher<int> m2 = MatcherCast<int>(m1);
                EXPECT_TRUE(m2.Matches(2));
                EXPECT_FALSE(m2.Matches(3));

                Matcher<IntValue> m3 = Truly(IsPositiveIntValue);
                Matcher<int> m4 = MatcherCast<int>(m3);
                // In the following, the arguments 1 and 0 are statically converted
                // to IntValue objects, and then tested by the IsPositiveIntValue()
                // predicate.
                EXPECT_TRUE(m4.Matches(1));
                EXPECT_FALSE(m4.Matches(0));
            }

// Tests that MatcherCast<T>(m) works when m is a Matcher<const T&>.
            TEST(MatcherCastTest, FromConstReferenceToNonReference) {
                Matcher<const int &> m1 = Eq(0);
                Matcher<int> m2 = MatcherCast<int>(m1);
                EXPECT_TRUE(m2.Matches(0));
                EXPECT_FALSE(m2.Matches(1));
            }

// Tests that MatcherCast<T>(m) works when m is a Matcher<T&>.
            TEST(MatcherCastTest, FromReferenceToNonReference) {
                Matcher<int &> m1 = Eq(0);
                Matcher<int> m2 = MatcherCast<int>(m1);
                EXPECT_TRUE(m2.Matches(0));
                EXPECT_FALSE(m2.Matches(1));
            }

// Tests that MatcherCast<const T&>(m) works when m is a Matcher<T>.
            TEST(MatcherCastTest, FromNonReferenceToConstReference) {
                Matcher<int> m1 = Eq(0);
                Matcher<const int &> m2 = MatcherCast<const int &>(m1);
                EXPECT_TRUE(m2.Matches(0));
                EXPECT_FALSE(m2.Matches(1));
            }

// Tests that MatcherCast<T&>(m) works when m is a Matcher<T>.
            TEST(MatcherCastTest, FromNonReferenceToReference) {
                Matcher<int> m1 = Eq(0);
                Matcher<int &> m2 = MatcherCast<int &>(m1);
                int n = 0;
                EXPECT_TRUE(m2.Matches(n));
                n = 1;
                EXPECT_FALSE(m2.Matches(n));
            }

// Tests that MatcherCast<T>(m) works when m is a Matcher<T>.
            TEST(MatcherCastTest, FromSameType) {
                Matcher<int> m1 = Eq(0);
                Matcher<int> m2 = MatcherCast<int>(m1);
                EXPECT_TRUE(m2.Matches(0));
                EXPECT_FALSE(m2.Matches(1));
            }

// Tests that MatcherCast<T>(m) works when m is a value of the same type as the
// value type of the Matcher.
            TEST(MatcherCastTest, FromAValue) {
                Matcher<int> m = MatcherCast<int>(42);
                EXPECT_TRUE(m.Matches(42));
                EXPECT_FALSE(m.Matches(239));
            }

// Tests that MatcherCast<T>(m) works when m is a value of the type implicitly
// convertible to the value type of the Matcher.
            TEST(MatcherCastTest, FromAnImplicitlyConvertibleValue) {
                const int kExpected = 'c';
                Matcher<int> m = MatcherCast<int>('c');
                EXPECT_TRUE(m.Matches(kExpected));
                EXPECT_FALSE(m.Matches(kExpected + 1));
            }

            struct NonImplicitlyConstructibleTypeWithOperatorEq {
                friend bool operator==(
                        const NonImplicitlyConstructibleTypeWithOperatorEq & /* ignored */,
                        int rhs) {
                    return 42 == rhs;
                }

                friend bool operator==(
                        int lhs,
                        const NonImplicitlyConstructibleTypeWithOperatorEq & /* ignored */) {
                    return lhs == 42;
                }
            };

// Tests that MatcherCast<T>(m) works when m is a neither a matcher nor
// implicitly convertible to the value type of the Matcher, but the value type
// of the matcher has operator==() overload accepting m.
            TEST(MatcherCastTest, NonImplicitlyConstructibleTypeWithOperatorEq) {
                Matcher<NonImplicitlyConstructibleTypeWithOperatorEq> m1 =
                        MatcherCast<NonImplicitlyConstructibleTypeWithOperatorEq>(42);
                EXPECT_TRUE(m1.Matches(NonImplicitlyConstructibleTypeWithOperatorEq()));

                Matcher<NonImplicitlyConstructibleTypeWithOperatorEq> m2 =
                        MatcherCast<NonImplicitlyConstructibleTypeWithOperatorEq>(239);
                EXPECT_FALSE(m2.Matches(NonImplicitlyConstructibleTypeWithOperatorEq()));

                // When updating the following lines please also change the comment to
                // namespace convertible_from_any.
                Matcher<int> m3 =
                        MatcherCast<int>(NonImplicitlyConstructibleTypeWithOperatorEq());
                EXPECT_TRUE(m3.Matches(42));
                EXPECT_FALSE(m3.Matches(239));
            }

// ConvertibleFromAny does not work with MSVC. resulting in
// error C2440: 'initializing': cannot convert from 'Eq' to 'M'
// No constructor could take the source type, or constructor overload
// resolution was ambiguous

#if !defined _MSC_VER

// The below ConvertibleFromAny struct is implicitly constructible from anything
// and when in the same namespace can interact with other tests. In particular,
// if it is in the same namespace as other tests and one removes
//   NonImplicitlyConstructibleTypeWithOperatorEq::operator==(int lhs, ...);
// then the corresponding test still compiles (and it should not!) by implicitly
// converting NonImplicitlyConstructibleTypeWithOperatorEq to ConvertibleFromAny
// in m3.Matcher().
            namespace convertible_from_any {
// Implicitly convertible from any type.
                struct ConvertibleFromAny {
                    ConvertibleFromAny(int a_value) : value(a_value) {}

                    template<typename T>
                    ConvertibleFromAny(const T & /*a_value*/) : value(-1) {
                        ADD_FAILURE() << "Conversion constructor called";
                    }

                    int value;
                };

                bool operator==(const ConvertibleFromAny &a, const ConvertibleFromAny &b) {
                    return a.value == b.value;
                }

                ostream &operator<<(ostream &os, const ConvertibleFromAny &a) {
                    return os << a.value;
                }

                TEST(MatcherCastTest, ConversionConstructorIsUsed) {
                    Matcher<ConvertibleFromAny> m = MatcherCast<ConvertibleFromAny>(1);
                    EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
                    EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
                }

                TEST(MatcherCastTest, FromConvertibleFromAny) {
                    Matcher<ConvertibleFromAny> m =
                            MatcherCast<ConvertibleFromAny>(Eq(ConvertibleFromAny(1)));
                    EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
                    EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
                }
            }  // namespace convertible_from_any

#endif  // !defined _MSC_VER

            struct IntReferenceWrapper {
                IntReferenceWrapper(const int &a_value) : value(&a_value) {}

                const int *value;
            };

            bool operator==(const IntReferenceWrapper &a, const IntReferenceWrapper &b) {
                return a.value == b.value;
            }

            TEST(MatcherCastTest, ValueIsNotCopied) {
                int n = 42;
                Matcher<IntReferenceWrapper> m = MatcherCast<IntReferenceWrapper>(n);
                // Verify that the matcher holds a reference to n, not to its temporary copy.
                EXPECT_TRUE(m.Matches(n));
            }

            class Base {
            public:
                virtual ~Base() {}

                Base() {}

            private:
                GTEST_DISALLOW_COPY_AND_ASSIGN_(Base);
            };

            class Derived : public Base {
            public:
                Derived() : Base() {}

                int i;
            };

            class OtherDerived : public Base {
            };

// Tests that SafeMatcherCast<T>(m) works when m is a polymorphic matcher.
            TEST(SafeMatcherCastTest, FromPolymorphicMatcher) {
                Matcher<char> m2 = SafeMatcherCast<char>(Eq(32));
                EXPECT_TRUE(m2.Matches(' '));
                EXPECT_FALSE(m2.Matches('\n'));
            }

// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<U> where
// T and U are arithmetic types and T can be losslessly converted to
// U.
            TEST(SafeMatcherCastTest, FromLosslesslyConvertibleArithmeticType) {
                Matcher<double> m1 = DoubleEq(1.0);
                Matcher<float> m2 = SafeMatcherCast<float>(m1);
                EXPECT_TRUE(m2.Matches(1.0f));
                EXPECT_FALSE(m2.Matches(2.0f));

                Matcher<char> m3 = SafeMatcherCast<char>(TypedEq<int>('a'));
                EXPECT_TRUE(m3.Matches('a'));
                EXPECT_FALSE(m3.Matches('b'));
            }

// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<U> where T and U
// are pointers or references to a derived and a base class, correspondingly.
            TEST(SafeMatcherCastTest, FromBaseClass) {
                Derived d, d2;
                Matcher<Base *> m1 = Eq(&d);
                Matcher<Derived *> m2 = SafeMatcherCast<Derived *>(m1);
                EXPECT_TRUE(m2.Matches(&d));
                EXPECT_FALSE(m2.Matches(&d2));

                Matcher<Base &> m3 = Ref(d);
                Matcher<Derived &> m4 = SafeMatcherCast<Derived &>(m3);
                EXPECT_TRUE(m4.Matches(d));
                EXPECT_FALSE(m4.Matches(d2));
            }

// Tests that SafeMatcherCast<T&>(m) works when m is a Matcher<const T&>.
            TEST(SafeMatcherCastTest, FromConstReferenceToReference) {
                int n = 0;
                Matcher<const int &> m1 = Ref(n);
                Matcher<int &> m2 = SafeMatcherCast<int &>(m1);
                int n1 = 0;
                EXPECT_TRUE(m2.Matches(n));
                EXPECT_FALSE(m2.Matches(n1));
            }

// Tests that MatcherCast<const T&>(m) works when m is a Matcher<T>.
            TEST(SafeMatcherCastTest, FromNonReferenceToConstReference) {
                Matcher<int> m1 = Eq(0);
                Matcher<const int &> m2 = SafeMatcherCast<const int &>(m1);
                EXPECT_TRUE(m2.Matches(0));
                EXPECT_FALSE(m2.Matches(1));
            }

// Tests that SafeMatcherCast<T&>(m) works when m is a Matcher<T>.
            TEST(SafeMatcherCastTest, FromNonReferenceToReference) {
                Matcher<int> m1 = Eq(0);
                Matcher<int &> m2 = SafeMatcherCast<int &>(m1);
                int n = 0;
                EXPECT_TRUE(m2.Matches(n));
                n = 1;
                EXPECT_FALSE(m2.Matches(n));
            }

// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<T>.
            TEST(SafeMatcherCastTest, FromSameType) {
                Matcher<int> m1 = Eq(0);
                Matcher<int> m2 = SafeMatcherCast<int>(m1);
                EXPECT_TRUE(m2.Matches(0));
                EXPECT_FALSE(m2.Matches(1));
            }

#if !defined _MSC_VER

            namespace convertible_from_any {
                TEST(SafeMatcherCastTest, ConversionConstructorIsUsed) {
                    Matcher<ConvertibleFromAny> m = SafeMatcherCast<ConvertibleFromAny>(1);
                    EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
                    EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
                }

                TEST(SafeMatcherCastTest, FromConvertibleFromAny) {
                    Matcher<ConvertibleFromAny> m =
                            SafeMatcherCast<ConvertibleFromAny>(Eq(ConvertibleFromAny(1)));
                    EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
                    EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
                }
            }  // namespace convertible_from_any

#endif  // !defined _MSC_VER

            TEST(SafeMatcherCastTest, ValueIsNotCopied) {
                int n = 42;
                Matcher<IntReferenceWrapper> m = SafeMatcherCast<IntReferenceWrapper>(n);
                // Verify that the matcher holds a reference to n, not to its temporary copy.
                EXPECT_TRUE(m.Matches(n));
            }

            TEST(ExpectThat, TakesLiterals) {
                EXPECT_THAT(1, 1);
                EXPECT_THAT(1.0, 1.0);
                EXPECT_THAT(std::string(), "");
            }

            TEST(ExpectThat, TakesFunctions) {
                struct Helper {
                    static void Func() {}
                };
                void (*func)() = Helper::Func;
                EXPECT_THAT(func, Helper::Func);
                EXPECT_THAT(func, &Helper::Func);
            }

// Tests that A<T>() matches any value of type T.
            TEST(ATest, MatchesAnyValue) {
                // Tests a matcher for a value type.
                Matcher<double> m1 = A<double>();
                EXPECT_TRUE(m1.Matches(91.43));
                EXPECT_TRUE(m1.Matches(-15.32));

                // Tests a matcher for a reference type.
                int a = 2;
                int b = -6;
                Matcher<int &> m2 = A<int &>();
                EXPECT_TRUE(m2.Matches(a));
                EXPECT_TRUE(m2.Matches(b));
            }

            TEST(ATest, WorksForDerivedClass) {
                Base base;
                Derived derived;
                EXPECT_THAT(&base, A<Base *>());
                // This shouldn't compile: EXPECT_THAT(&base, A<Derived*>());
                EXPECT_THAT(&derived, A<Base *>());
                EXPECT_THAT(&derived, A<Derived *>());
            }

// Tests that A<T>() describes itself properly.
            TEST(ATest, CanDescribeSelf) {
                EXPECT_EQ("is anything", Describe(A<bool>()));
            }

// Tests that An<T>() matches any value of type T.
            TEST(AnTest, MatchesAnyValue) {
                // Tests a matcher for a value type.
                Matcher<int> m1 = An<int>();
                EXPECT_TRUE(m1.Matches(9143));
                EXPECT_TRUE(m1.Matches(-1532));

                // Tests a matcher for a reference type.
                int a = 2;
                int b = -6;
                Matcher<int &> m2 = An<int &>();
                EXPECT_TRUE(m2.Matches(a));
                EXPECT_TRUE(m2.Matches(b));
            }

// Tests that An<T>() describes itself properly.
            TEST(AnTest, CanDescribeSelf) {
                EXPECT_EQ("is anything", Describe(An<int>()));
            }

// Tests that _ can be used as a matcher for any type and matches any
// value of that type.
            TEST(UnderscoreTest, MatchesAnyValue) {
                // Uses _ as a matcher for a value type.
                Matcher<int> m1 = _;
                EXPECT_TRUE(m1.Matches(123));
                EXPECT_TRUE(m1.Matches(-242));

                // Uses _ as a matcher for a reference type.
                bool a = false;
                const bool b = true;
                Matcher<const bool &> m2 = _;
                EXPECT_TRUE(m2.Matches(a));
                EXPECT_TRUE(m2.Matches(b));
            }

// Tests that _ describes itself properly.
            TEST(UnderscoreTest, CanDescribeSelf) {
                Matcher<int> m = _;
                EXPECT_EQ("is anything", Describe(m));
            }

// Tests that Eq(x) matches any value equal to x.
            TEST(EqTest, MatchesEqualValue) {
                // 2 C-strings with same content but different addresses.
                const char a1[] = "hi";
                const char a2[] = "hi";

                Matcher<const char *> m1 = Eq(a1);
                EXPECT_TRUE(m1.Matches(a1));
                EXPECT_FALSE(m1.Matches(a2));
            }

// Tests that Eq(v) describes itself properly.

            class Unprintable {
            public:
                Unprintable() : c_('a') {}

                bool operator==(const Unprintable & /* rhs */) const { return true; }

                // -Wunused-private-field: dummy accessor for `c_`.
                char dummy_c() { return c_; }

            private:
                char c_;
            };

            TEST(EqTest, CanDescribeSelf) {
                Matcher<Unprintable> m = Eq(Unprintable());
                EXPECT_EQ("is equal to 1-byte object <61>", Describe(m));
            }

// Tests that Eq(v) can be used to match any type that supports
// comparing with type T, where T is v's type.
            TEST(EqTest, IsPolymorphic) {
                Matcher<int> m1 = Eq(1);
                EXPECT_TRUE(m1.Matches(1));
                EXPECT_FALSE(m1.Matches(2));

                Matcher<char> m2 = Eq(1);
                EXPECT_TRUE(m2.Matches('\1'));
                EXPECT_FALSE(m2.Matches('a'));
            }

// Tests that TypedEq<T>(v) matches values of type T that's equal to v.
            TEST(TypedEqTest, ChecksEqualityForGivenType) {
                Matcher<char> m1 = TypedEq<char>('a');
                EXPECT_TRUE(m1.Matches('a'));
                EXPECT_FALSE(m1.Matches('b'));

                Matcher<int> m2 = TypedEq<int>(6);
                EXPECT_TRUE(m2.Matches(6));
                EXPECT_FALSE(m2.Matches(7));
            }

// Tests that TypedEq(v) describes itself properly.
            TEST(TypedEqTest, CanDescribeSelf) {
                EXPECT_EQ("is equal to 2", Describe(TypedEq<int>(2)));
            }

// Tests that TypedEq<T>(v) has type Matcher<T>.

// Type<T>::IsTypeOf(v) compiles if and only if the type of value v is T, where
// T is a "bare" type (i.e. not in the form of const U or U&).  If v's type is
// not T, the compiler will generate a message about "undefined reference".
            template<typename T>
            struct Type {
                static bool IsTypeOf(const T & /* v */) { return true; }

                template<typename T2>
                static void IsTypeOf(T2 v);
            };

            TEST(TypedEqTest, HasSpecifiedType) {
                // Verfies that the type of TypedEq<T>(v) is Matcher<T>.
                Type<Matcher<int> >::IsTypeOf(TypedEq<int>(5));
                Type<Matcher<double> >::IsTypeOf(TypedEq<double>(5));
            }

// Tests that Ge(v) matches anything >= v.
            TEST(GeTest, ImplementsGreaterThanOrEqual) {
                Matcher<int> m1 = Ge(0);
                EXPECT_TRUE(m1.Matches(1));
                EXPECT_TRUE(m1.Matches(0));
                EXPECT_FALSE(m1.Matches(-1));
            }

// Tests that Ge(v) describes itself properly.
            TEST(GeTest, CanDescribeSelf) {
                Matcher<int> m = Ge(5);
                EXPECT_EQ("is >= 5", Describe(m));
            }

// Tests that Gt(v) matches anything > v.
            TEST(GtTest, ImplementsGreaterThan) {
                Matcher<double> m1 = Gt(0);
                EXPECT_TRUE(m1.Matches(1.0));
                EXPECT_FALSE(m1.Matches(0.0));
                EXPECT_FALSE(m1.Matches(-1.0));
            }

// Tests that Gt(v) describes itself properly.
            TEST(GtTest, CanDescribeSelf) {
                Matcher<int> m = Gt(5);
                EXPECT_EQ("is > 5", Describe(m));
            }

// Tests that Le(v) matches anything <= v.
            TEST(LeTest, ImplementsLessThanOrEqual) {
                Matcher<char> m1 = Le('b');
                EXPECT_TRUE(m1.Matches('a'));
                EXPECT_TRUE(m1.Matches('b'));
                EXPECT_FALSE(m1.Matches('c'));
            }

// Tests that Le(v) describes itself properly.
            TEST(LeTest, CanDescribeSelf) {
                Matcher<int> m = Le(5);
                EXPECT_EQ("is <= 5", Describe(m));
            }

// Tests that Lt(v) matches anything < v.
            TEST(LtTest, ImplementsLessThan) {
                Matcher<const std::string &> m1 = Lt("Hello");
                EXPECT_TRUE(m1.Matches("Abc"));
                EXPECT_FALSE(m1.Matches("Hello"));
                EXPECT_FALSE(m1.Matches("Hello, world!"));
            }

// Tests that Lt(v) describes itself properly.
            TEST(LtTest, CanDescribeSelf) {
                Matcher<int> m = Lt(5);
                EXPECT_EQ("is < 5", Describe(m));
            }

// Tests that Ne(v) matches anything != v.
            TEST(NeTest, ImplementsNotEqual) {
                Matcher<int> m1 = Ne(0);
                EXPECT_TRUE(m1.Matches(1));
                EXPECT_TRUE(m1.Matches(-1));
                EXPECT_FALSE(m1.Matches(0));
            }

// Tests that Ne(v) describes itself properly.
            TEST(NeTest, CanDescribeSelf) {
                Matcher<int> m = Ne(5);
                EXPECT_EQ("isn't equal to 5", Describe(m));
            }

            class MoveOnly {
            public:
                explicit MoveOnly(int i) : i_(i) {}

                MoveOnly(const MoveOnly &) = delete;

                MoveOnly(MoveOnly &&) = default;

                MoveOnly &operator=(const MoveOnly &) = delete;

                MoveOnly &operator=(MoveOnly &&) = default;

                bool operator==(const MoveOnly &other) const { return i_ == other.i_; }

                bool operator!=(const MoveOnly &other) const { return i_ != other.i_; }

                bool operator<(const MoveOnly &other) const { return i_ < other.i_; }

                bool operator<=(const MoveOnly &other) const { return i_ <= other.i_; }

                bool operator>(const MoveOnly &other) const { return i_ > other.i_; }

                bool operator>=(const MoveOnly &other) const { return i_ >= other.i_; }

            private:
                int i_;
            };

            struct MoveHelper {
                MOCK_METHOD1(Call, void(MoveOnly));
            };

            TEST(ComparisonBaseTest, WorksWithMoveOnly) {
                MoveOnly m{0};
                MoveHelper helper;

                EXPECT_CALL(helper, Call(Eq(ByRef(m))));
                helper.Call(MoveOnly(0));
                EXPECT_CALL(helper, Call(Ne(ByRef(m))));
                helper.Call(MoveOnly(1));
                EXPECT_CALL(helper, Call(Le(ByRef(m))));
                helper.Call(MoveOnly(0));
                EXPECT_CALL(helper, Call(Lt(ByRef(m))));
                helper.Call(MoveOnly(-1));
                EXPECT_CALL(helper, Call(Ge(ByRef(m))));
                helper.Call(MoveOnly(0));
                EXPECT_CALL(helper, Call(Gt(ByRef(m))));
                helper.Call(MoveOnly(1));
            }

// Tests that IsNull() matches any NULL pointer of any type.
            TEST(IsNullTest, MatchesNullPointer) {
                Matcher<int *> m1 = IsNull();
                int *p1 = nullptr;
                int n = 0;
                EXPECT_TRUE(m1.Matches(p1));
                EXPECT_FALSE(m1.Matches(&n));

                Matcher<const char *> m2 = IsNull();
                const char *p2 = nullptr;
                EXPECT_TRUE(m2.Matches(p2));
                EXPECT_FALSE(m2.Matches("hi"));

                Matcher<void *> m3 = IsNull();
                void *p3 = nullptr;
                EXPECT_TRUE(m3.Matches(p3));
                EXPECT_FALSE(m3.Matches(reinterpret_cast<void *>(0xbeef)));
            }

            TEST(IsNullTest, StdFunction) {
                const Matcher<std::function<void()>> m = IsNull();

                EXPECT_TRUE(m.Matches(std::function<void()>()));
                EXPECT_FALSE(m.Matches([] {}));
            }

// Tests that IsNull() describes itself properly.
            TEST(IsNullTest, CanDescribeSelf) {
                Matcher<int *> m = IsNull();
                EXPECT_EQ("is NULL", Describe(m));
                EXPECT_EQ("isn't NULL", DescribeNegation(m));
            }

// Tests that NotNull() matches any non-NULL pointer of any type.
            TEST(NotNullTest, MatchesNonNullPointer) {
                Matcher<int *> m1 = NotNull();
                int *p1 = nullptr;
                int n = 0;
                EXPECT_FALSE(m1.Matches(p1));
                EXPECT_TRUE(m1.Matches(&n));

                Matcher<const char *> m2 = NotNull();
                const char *p2 = nullptr;
                EXPECT_FALSE(m2.Matches(p2));
                EXPECT_TRUE(m2.Matches("hi"));
            }

            TEST(NotNullTest, LinkedPtr) {
                const Matcher<std::shared_ptr<int>> m = NotNull();
                const std::shared_ptr<int> null_p;
                const std::shared_ptr<int> non_null_p(new int);

                EXPECT_FALSE(m.Matches(null_p));
                EXPECT_TRUE(m.Matches(non_null_p));
            }

            TEST(NotNullTest, ReferenceToConstLinkedPtr) {
                const Matcher<const std::shared_ptr<double> &> m = NotNull();
                const std::shared_ptr<double> null_p;
                const std::shared_ptr<double> non_null_p(new double);

                EXPECT_FALSE(m.Matches(null_p));
                EXPECT_TRUE(m.Matches(non_null_p));
            }

            TEST(NotNullTest, StdFunction) {
                const Matcher<std::function<void()>> m = NotNull();

                EXPECT_TRUE(m.Matches([] {}));
                EXPECT_FALSE(m.Matches(std::function<void()>()));
            }

// Tests that NotNull() describes itself properly.
            TEST(NotNullTest, CanDescribeSelf) {
                Matcher<int *> m = NotNull();
                EXPECT_EQ("isn't NULL", Describe(m));
            }

// Tests that Ref(variable) matches an argument that references
// 'variable'.
            TEST(RefTest, MatchesSameVariable) {
                int a = 0;
                int b = 0;
                Matcher<int &> m = Ref(a);
                EXPECT_TRUE(m.Matches(a));
                EXPECT_FALSE(m.Matches(b));
            }

// Tests that Ref(variable) describes itself properly.
            TEST(RefTest, CanDescribeSelf) {
                int n = 5;
                Matcher<int &> m = Ref(n);
                stringstream ss;
                ss << "references the variable @" << &n << " 5";
                EXPECT_EQ(ss.str(), Describe(m));
            }

// Test that Ref(non_const_varialbe) can be used as a matcher for a
// const reference.
            TEST(RefTest, CanBeUsedAsMatcherForConstReference) {
                int a = 0;
                int b = 0;
                Matcher<const int &> m = Ref(a);
                EXPECT_TRUE(m.Matches(a));
                EXPECT_FALSE(m.Matches(b));
            }

// Tests that Ref(variable) is covariant, i.e. Ref(derived) can be
// used wherever Ref(base) can be used (Ref(derived) is a sub-type
// of Ref(base), but not vice versa.

            TEST(RefTest, IsCovariant) {
                Base base, base2;
                Derived derived;
                Matcher<const Base &> m1 = Ref(base);
                EXPECT_TRUE(m1.Matches(base));
                EXPECT_FALSE(m1.Matches(base2));
                EXPECT_FALSE(m1.Matches(derived));

                m1 = Ref(derived);
                EXPECT_TRUE(m1.Matches(derived));
                EXPECT_FALSE(m1.Matches(base));
                EXPECT_FALSE(m1.Matches(base2));
            }

            TEST(RefTest, ExplainsResult) {
                int n = 0;
                EXPECT_THAT(Explain(Matcher<const int &>(Ref(n)), n),
                            StartsWith("which is located @"));

                int m = 0;
                EXPECT_THAT(Explain(Matcher<const int &>(Ref(n)), m),
                            StartsWith("which is located @"));
            }

// Tests string comparison matchers.

            TEST(StrEqTest, MatchesEqualString) {
                Matcher<const char *> m = StrEq(std::string("Hello"));
                EXPECT_TRUE(m.Matches("Hello"));
                EXPECT_FALSE(m.Matches("hello"));
                EXPECT_FALSE(m.Matches(nullptr));

                Matcher<const std::string &> m2 = StrEq("Hello");
                EXPECT_TRUE(m2.Matches("Hello"));
                EXPECT_FALSE(m2.Matches("Hi"));

#if GTEST_HAS_ABSL
                                                                                                                                        Matcher<const absl::string_view&> m3 = StrEq("Hello");
  EXPECT_TRUE(m3.Matches(absl::string_view("Hello")));
  EXPECT_FALSE(m3.Matches(absl::string_view("hello")));
  EXPECT_FALSE(m3.Matches(absl::string_view()));

  Matcher<const absl::string_view&> m_empty = StrEq("");
  EXPECT_TRUE(m_empty.Matches(absl::string_view("")));
  EXPECT_TRUE(m_empty.Matches(absl::string_view()));
  EXPECT_FALSE(m_empty.Matches(absl::string_view("hello")));
#endif  // GTEST_HAS_ABSL
            }

            TEST(StrEqTest, CanDescribeSelf) {
                Matcher<std::string> m = StrEq("Hi-\'\"?\\\a\b\f\n\r\t\v\xD3");
                EXPECT_EQ("is equal to \"Hi-\'\\\"?\\\\\\a\\b\\f\\n\\r\\t\\v\\xD3\"",
                          Describe(m));

                std::string str("01204500800");
                str[3] = '\0';
                Matcher<std::string> m2 = StrEq(str);
                EXPECT_EQ("is equal to \"012\\04500800\"", Describe(m2));
                str[0] = str[6] = str[7] = str[9] = str[10] = '\0';
                Matcher<std::string> m3 = StrEq(str);
                EXPECT_EQ("is equal to \"\\012\\045\\0\\08\\0\\0\"", Describe(m3));
            }

            TEST(StrNeTest, MatchesUnequalString) {
                Matcher<const char *> m = StrNe("Hello");
                EXPECT_TRUE(m.Matches(""));
                EXPECT_TRUE(m.Matches(nullptr));
                EXPECT_FALSE(m.Matches("Hello"));

                Matcher<std::string> m2 = StrNe(std::string("Hello"));
                EXPECT_TRUE(m2.Matches("hello"));
                EXPECT_FALSE(m2.Matches("Hello"));

#if GTEST_HAS_ABSL
                                                                                                                                        Matcher<const absl::string_view> m3 = StrNe("Hello");
  EXPECT_TRUE(m3.Matches(absl::string_view("")));
  EXPECT_TRUE(m3.Matches(absl::string_view()));
  EXPECT_FALSE(m3.Matches(absl::string_view("Hello")));
#endif  // GTEST_HAS_ABSL
            }

            TEST(StrNeTest, CanDescribeSelf) {
                Matcher<const char *> m = StrNe("Hi");
                EXPECT_EQ("isn't equal to \"Hi\"", Describe(m));
            }

            TEST(StrCaseEqTest, MatchesEqualStringIgnoringCase) {
                Matcher<const char *> m = StrCaseEq(std::string("Hello"));
                EXPECT_TRUE(m.Matches("Hello"));
                EXPECT_TRUE(m.Matches("hello"));
                EXPECT_FALSE(m.Matches("Hi"));
                EXPECT_FALSE(m.Matches(nullptr));

                Matcher<const std::string &> m2 = StrCaseEq("Hello");
                EXPECT_TRUE(m2.Matches("hello"));
                EXPECT_FALSE(m2.Matches("Hi"));

#if GTEST_HAS_ABSL
                                                                                                                                        Matcher<const absl::string_view&> m3 = StrCaseEq(std::string("Hello"));
  EXPECT_TRUE(m3.Matches(absl::string_view("Hello")));
  EXPECT_TRUE(m3.Matches(absl::string_view("hello")));
  EXPECT_FALSE(m3.Matches(absl::string_view("Hi")));
  EXPECT_FALSE(m3.Matches(absl::string_view()));
#endif  // GTEST_HAS_ABSL
            }

            TEST(StrCaseEqTest, MatchesEqualStringWith0IgnoringCase) {
                std::string str1("oabocdooeoo");
                std::string str2("OABOCDOOEOO");
                Matcher<const std::string &> m0 = StrCaseEq(str1);
                EXPECT_FALSE(m0.Matches(str2 + std::string(1, '\0')));

                str1[3] = str2[3] = '\0';
                Matcher<const std::string &> m1 = StrCaseEq(str1);
                EXPECT_TRUE(m1.Matches(str2));

                str1[0] = str1[6] = str1[7] = str1[10] = '\0';
                str2[0] = str2[6] = str2[7] = str2[10] = '\0';
                Matcher<const std::string &> m2 = StrCaseEq(str1);
                str1[9] = str2[9] = '\0';
                EXPECT_FALSE(m2.Matches(str2));

                Matcher<const std::string &> m3 = StrCaseEq(str1);
                EXPECT_TRUE(m3.Matches(str2));

                EXPECT_FALSE(m3.Matches(str2 + "x"));
                str2.append(1, '\0');
                EXPECT_FALSE(m3.Matches(str2));
                EXPECT_FALSE(m3.Matches(std::string(str2, 0, 9)));
            }

            TEST(StrCaseEqTest, CanDescribeSelf) {
                Matcher<std::string> m = StrCaseEq("Hi");
                EXPECT_EQ("is equal to (ignoring case) \"Hi\"", Describe(m));
            }

            TEST(StrCaseNeTest, MatchesUnequalStringIgnoringCase) {
                Matcher<const char *> m = StrCaseNe("Hello");
                EXPECT_TRUE(m.Matches("Hi"));
                EXPECT_TRUE(m.Matches(nullptr));
                EXPECT_FALSE(m.Matches("Hello"));
                EXPECT_FALSE(m.Matches("hello"));

                Matcher<std::string> m2 = StrCaseNe(std::string("Hello"));
                EXPECT_TRUE(m2.Matches(""));
                EXPECT_FALSE(m2.Matches("Hello"));

#if GTEST_HAS_ABSL
                                                                                                                                        Matcher<const absl::string_view> m3 = StrCaseNe("Hello");
  EXPECT_TRUE(m3.Matches(absl::string_view("Hi")));
  EXPECT_TRUE(m3.Matches(absl::string_view()));
  EXPECT_FALSE(m3.Matches(absl::string_view("Hello")));
  EXPECT_FALSE(m3.Matches(absl::string_view("hello")));
#endif  // GTEST_HAS_ABSL
            }

            TEST(StrCaseNeTest, CanDescribeSelf) {
                Matcher<const char *> m = StrCaseNe("Hi");
                EXPECT_EQ("isn't equal to (ignoring case) \"Hi\"", Describe(m));
            }

// Tests that HasSubstr() works for matching string-typed values.
            TEST(HasSubstrTest, WorksForStringClasses) {
                const Matcher<std::string> m1 = HasSubstr("foo");
                EXPECT_TRUE(m1.Matches(std::string("I love food.")));
                EXPECT_FALSE(m1.Matches(std::string("tofo")));

                const Matcher<const std::string &> m2 = HasSubstr("foo");
                EXPECT_TRUE(m2.Matches(std::string("I love food.")));
                EXPECT_FALSE(m2.Matches(std::string("tofo")));

                const Matcher<std::string> m_empty = HasSubstr("");
                EXPECT_TRUE(m_empty.Matches(std::string()));
                EXPECT_TRUE(m_empty.Matches(std::string("not empty")));
            }

// Tests that HasSubstr() works for matching C-string-typed values.
            TEST(HasSubstrTest, WorksForCStrings) {
                const Matcher<char *> m1 = HasSubstr("foo");
                EXPECT_TRUE(m1.Matches(const_cast<char *>("I love food.")));
                EXPECT_FALSE(m1.Matches(const_cast<char *>("tofo")));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const char *> m2 = HasSubstr("foo");
                EXPECT_TRUE(m2.Matches("I love food."));
                EXPECT_FALSE(m2.Matches("tofo"));
                EXPECT_FALSE(m2.Matches(nullptr));

                const Matcher<const char *> m_empty = HasSubstr("");
                EXPECT_TRUE(m_empty.Matches("not empty"));
                EXPECT_TRUE(m_empty.Matches(""));
                EXPECT_FALSE(m_empty.Matches(nullptr));
            }

#if GTEST_HAS_ABSL
                                                                                                                                    // Tests that HasSubstr() works for matching absl::string_view-typed values.
TEST(HasSubstrTest, WorksForStringViewClasses) {
  const Matcher<absl::string_view> m1 = HasSubstr("foo");
  EXPECT_TRUE(m1.Matches(absl::string_view("I love food.")));
  EXPECT_FALSE(m1.Matches(absl::string_view("tofo")));
  EXPECT_FALSE(m1.Matches(absl::string_view()));

  const Matcher<const absl::string_view&> m2 = HasSubstr("foo");
  EXPECT_TRUE(m2.Matches(absl::string_view("I love food.")));
  EXPECT_FALSE(m2.Matches(absl::string_view("tofo")));
  EXPECT_FALSE(m2.Matches(absl::string_view()));

  const Matcher<const absl::string_view&> m3 = HasSubstr("");
  EXPECT_TRUE(m3.Matches(absl::string_view("foo")));
  EXPECT_TRUE(m3.Matches(absl::string_view("")));
  EXPECT_TRUE(m3.Matches(absl::string_view()));
}
#endif  // GTEST_HAS_ABSL

// Tests that HasSubstr(s) describes itself properly.
            TEST(HasSubstrTest, CanDescribeSelf) {
                Matcher<std::string> m = HasSubstr("foo\n\"");
                EXPECT_EQ("has substring \"foo\\n\\\"\"", Describe(m));
            }

            TEST(KeyTest, CanDescribeSelf) {
                Matcher<const pair<std::string, int> &> m = Key("foo");
                EXPECT_EQ("has a key that is equal to \"foo\"", Describe(m));
                EXPECT_EQ("doesn't have a key that is equal to \"foo\"", DescribeNegation(m));
            }

            TEST(KeyTest, ExplainsResult) {
                Matcher<pair<int, bool> > m = Key(GreaterThan(10));
                EXPECT_EQ("whose first field is a value which is 5 less than 10",
                          Explain(m, make_pair(5, true)));
                EXPECT_EQ("whose first field is a value which is 5 more than 10",
                          Explain(m, make_pair(15, true)));
            }

            TEST(KeyTest, MatchesCorrectly) {
                pair<int, std::string> p(25, "foo");
                EXPECT_THAT(p, Key(25));
                EXPECT_THAT(p, Not(Key(42)));
                EXPECT_THAT(p, Key(Ge(20)));
                EXPECT_THAT(p, Not(Key(Lt(25))));
            }

            TEST(KeyTest, WorksWithMoveOnly) {
                pair<std::unique_ptr<int>, std::unique_ptr<int>> p;
                EXPECT_THAT(p, Key(Eq(nullptr)));
            }

            template<size_t I>
            struct Tag {
            };

            struct PairWithGet {
                int member_1;
                std::string member_2;
                using first_type = int;
                using second_type = std::string;

                const int &GetImpl(Tag<0>) const { return member_1; }

                const std::string &GetImpl(Tag<1>) const { return member_2; }
            };

            template<size_t I>
            auto get(const PairWithGet &value) -> decltype(value.GetImpl(Tag<I>())) {
                return value.GetImpl(Tag<I>());
            }

            TEST(PairTest, MatchesPairWithGetCorrectly) {
                PairWithGet p{25, "foo"};
                EXPECT_THAT(p, Key(25));
                EXPECT_THAT(p, Not(Key(42)));
                EXPECT_THAT(p, Key(Ge(20)));
                EXPECT_THAT(p, Not(Key(Lt(25))));

                std::vector<PairWithGet> v = {{11, "Foo"},
                                              {29, "gMockIsBestMock"}};
                EXPECT_THAT(v, Contains(Key(29)));
            }

            TEST(KeyTest, SafelyCastsInnerMatcher) {
                Matcher<int> is_positive = Gt(0);
                Matcher<int> is_negative = Lt(0);
                pair<char, bool> p('a', true);
                EXPECT_THAT(p, Key(is_positive));
                EXPECT_THAT(p, Not(Key(is_negative)));
            }

            TEST(KeyTest, InsideContainsUsingMap) {
                map<int, char> container;
                container.insert(make_pair(1, 'a'));
                container.insert(make_pair(2, 'b'));
                container.insert(make_pair(4, 'c'));
                EXPECT_THAT(container, Contains(Key(1)));
                EXPECT_THAT(container, Not(Contains(Key(3))));
            }

            TEST(KeyTest, InsideContainsUsingMultimap) {
                multimap<int, char> container;
                container.insert(make_pair(1, 'a'));
                container.insert(make_pair(2, 'b'));
                container.insert(make_pair(4, 'c'));

                EXPECT_THAT(container, Not(Contains(Key(25))));
                container.insert(make_pair(25, 'd'));
                EXPECT_THAT(container, Contains(Key(25)));
                container.insert(make_pair(25, 'e'));
                EXPECT_THAT(container, Contains(Key(25)));

                EXPECT_THAT(container, Contains(Key(1)));
                EXPECT_THAT(container, Not(Contains(Key(3))));
            }

            TEST(PairTest, Typing) {
                // Test verifies the following type conversions can be compiled.
                Matcher<const pair<const char *, int> &> m1 = Pair("foo", 42);
                Matcher<const pair<const char *, int> > m2 = Pair("foo", 42);
                Matcher<pair<const char *, int> > m3 = Pair("foo", 42);

                Matcher<pair<int, const std::string> > m4 = Pair(25, "42");
                Matcher<pair<const std::string, int> > m5 = Pair("25", 42);
            }

            TEST(PairTest, CanDescribeSelf) {
                Matcher<const pair<std::string, int> &> m1 = Pair("foo", 42);
                EXPECT_EQ("has a first field that is equal to \"foo\""
                          ", and has a second field that is equal to 42",
                          Describe(m1));
                EXPECT_EQ("has a first field that isn't equal to \"foo\""
                          ", or has a second field that isn't equal to 42",
                          DescribeNegation(m1));
                // Double and triple negation (1 or 2 times not and description of negation).
                Matcher<const pair<int, int> &> m2 = Not(Pair(Not(13), 42));
                EXPECT_EQ("has a first field that isn't equal to 13"
                          ", and has a second field that is equal to 42",
                          DescribeNegation(m2));
            }

            TEST(PairTest, CanExplainMatchResultTo) {
                // If neither field matches, Pair() should explain about the first
                // field.
                const Matcher<pair<int, int> > m = Pair(GreaterThan(0), GreaterThan(0));
                EXPECT_EQ("whose first field does not match, which is 1 less than 0",
                          Explain(m, make_pair(-1, -2)));

                // If the first field matches but the second doesn't, Pair() should
                // explain about the second field.
                EXPECT_EQ("whose second field does not match, which is 2 less than 0",
                          Explain(m, make_pair(1, -2)));

                // If the first field doesn't match but the second does, Pair()
                // should explain about the first field.
                EXPECT_EQ("whose first field does not match, which is 1 less than 0",
                          Explain(m, make_pair(-1, 2)));

                // If both fields match, Pair() should explain about them both.
                EXPECT_EQ("whose both fields match, where the first field is a value "
                          "which is 1 more than 0, and the second field is a value "
                          "which is 2 more than 0",
                          Explain(m, make_pair(1, 2)));

                // If only the first match has an explanation, only this explanation should
                // be printed.
                const Matcher<pair<int, int> > explain_first = Pair(GreaterThan(0), 0);
                EXPECT_EQ("whose both fields match, where the first field is a value "
                          "which is 1 more than 0",
                          Explain(explain_first, make_pair(1, 0)));

                // If only the second match has an explanation, only this explanation should
                // be printed.
                const Matcher<pair<int, int> > explain_second = Pair(0, GreaterThan(0));
                EXPECT_EQ("whose both fields match, where the second field is a value "
                          "which is 1 more than 0",
                          Explain(explain_second, make_pair(0, 1)));
            }

            TEST(PairTest, MatchesCorrectly) {
                pair<int, std::string> p(25, "foo");

                // Both fields match.
                EXPECT_THAT(p, Pair(25, "foo"));
                EXPECT_THAT(p, Pair(Ge(20), HasSubstr("o")));

                // 'first' doesnt' match, but 'second' matches.
                EXPECT_THAT(p, Not(Pair(42, "foo")));
                EXPECT_THAT(p, Not(Pair(Lt(25), "foo")));

                // 'first' matches, but 'second' doesn't match.
                EXPECT_THAT(p, Not(Pair(25, "bar")));
                EXPECT_THAT(p, Not(Pair(25, Not("foo"))));

                // Neither field matches.
                EXPECT_THAT(p, Not(Pair(13, "bar")));
                EXPECT_THAT(p, Not(Pair(Lt(13), HasSubstr("a"))));
            }

            TEST(PairTest, WorksWithMoveOnly) {
                pair<std::unique_ptr<int>, std::unique_ptr<int>> p;
                p.second.reset(new int(7));
                EXPECT_THAT(p, Pair(Eq(nullptr), Ne(nullptr)));
            }

            TEST(PairTest, SafelyCastsInnerMatchers) {
                Matcher<int> is_positive = Gt(0);
                Matcher<int> is_negative = Lt(0);
                pair<char, bool> p('a', true);
                EXPECT_THAT(p, Pair(is_positive, _));
                EXPECT_THAT(p, Not(Pair(is_negative, _)));
                EXPECT_THAT(p, Pair(_, is_positive));
                EXPECT_THAT(p, Not(Pair(_, is_negative)));
            }

            TEST(PairTest, InsideContainsUsingMap) {
                map<int, char> container;
                container.insert(make_pair(1, 'a'));
                container.insert(make_pair(2, 'b'));
                container.insert(make_pair(4, 'c'));
                EXPECT_THAT(container, Contains(Pair(1, 'a')));
                EXPECT_THAT(container, Contains(Pair(1, _)));
                EXPECT_THAT(container, Contains(Pair(_, 'a')));
                EXPECT_THAT(container, Not(Contains(Pair(3, _))));
            }

            TEST(ContainsTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(Contains(Pointee(2))));
                helper.Call(MakeUniquePtrs({1, 2}));
            }

            TEST(PairTest, UseGetInsteadOfMembers) {
                PairWithGet pair{7, "ABC"};
                EXPECT_THAT(pair, Pair(7, "ABC"));
                EXPECT_THAT(pair, Pair(Ge(7), HasSubstr("AB")));
                EXPECT_THAT(pair, Not(Pair(Lt(7), "ABC")));

                std::vector<PairWithGet> v = {{11, "Foo"},
                                              {29, "gMockIsBestMock"}};
                EXPECT_THAT(v,
                            ElementsAre(Pair(11, std::string("Foo")), Pair(Ge(10), Not(""))));
            }

// Tests StartsWith(s).

            TEST(StartsWithTest, MatchesStringWithGivenPrefix) {
                const Matcher<const char *> m1 = StartsWith(std::string(""));
                EXPECT_TRUE(m1.Matches("Hi"));
                EXPECT_TRUE(m1.Matches(""));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const std::string &> m2 = StartsWith("Hi");
                EXPECT_TRUE(m2.Matches("Hi"));
                EXPECT_TRUE(m2.Matches("Hi Hi!"));
                EXPECT_TRUE(m2.Matches("High"));
                EXPECT_FALSE(m2.Matches("H"));
                EXPECT_FALSE(m2.Matches(" Hi"));

#if GTEST_HAS_ABSL
                                                                                                                                        const Matcher<absl::string_view> m_empty = StartsWith("");
  EXPECT_TRUE(m_empty.Matches(absl::string_view()));
  EXPECT_TRUE(m_empty.Matches(absl::string_view("")));
  EXPECT_TRUE(m_empty.Matches(absl::string_view("not empty")));
#endif  // GTEST_HAS_ABSL
            }

            TEST(StartsWithTest, CanDescribeSelf) {
                Matcher<const std::string> m = StartsWith("Hi");
                EXPECT_EQ("starts with \"Hi\"", Describe(m));
            }

// Tests EndsWith(s).

            TEST(EndsWithTest, MatchesStringWithGivenSuffix) {
                const Matcher<const char *> m1 = EndsWith("");
                EXPECT_TRUE(m1.Matches("Hi"));
                EXPECT_TRUE(m1.Matches(""));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const std::string &> m2 = EndsWith(std::string("Hi"));
                EXPECT_TRUE(m2.Matches("Hi"));
                EXPECT_TRUE(m2.Matches("Wow Hi Hi"));
                EXPECT_TRUE(m2.Matches("Super Hi"));
                EXPECT_FALSE(m2.Matches("i"));
                EXPECT_FALSE(m2.Matches("Hi "));

#if GTEST_HAS_ABSL
                                                                                                                                        const Matcher<const absl::string_view&> m4 = EndsWith("");
  EXPECT_TRUE(m4.Matches("Hi"));
  EXPECT_TRUE(m4.Matches(""));
  EXPECT_TRUE(m4.Matches(absl::string_view()));
  EXPECT_TRUE(m4.Matches(absl::string_view("")));
#endif  // GTEST_HAS_ABSL
            }

            TEST(EndsWithTest, CanDescribeSelf) {
                Matcher<const std::string> m = EndsWith("Hi");
                EXPECT_EQ("ends with \"Hi\"", Describe(m));
            }

// Tests MatchesRegex().

            TEST(MatchesRegexTest, MatchesStringMatchingGivenRegex) {
                const Matcher<const char *> m1 = MatchesRegex("a.*z");
                EXPECT_TRUE(m1.Matches("az"));
                EXPECT_TRUE(m1.Matches("abcz"));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const std::string &> m2 = MatchesRegex(new RE("a.*z"));
                EXPECT_TRUE(m2.Matches("azbz"));
                EXPECT_FALSE(m2.Matches("az1"));
                EXPECT_FALSE(m2.Matches("1az"));

#if GTEST_HAS_ABSL
                                                                                                                                        const Matcher<const absl::string_view&> m3 = MatchesRegex("a.*z");
  EXPECT_TRUE(m3.Matches(absl::string_view("az")));
  EXPECT_TRUE(m3.Matches(absl::string_view("abcz")));
  EXPECT_FALSE(m3.Matches(absl::string_view("1az")));
  EXPECT_FALSE(m3.Matches(absl::string_view()));
  const Matcher<const absl::string_view&> m4 = MatchesRegex("");
  EXPECT_TRUE(m4.Matches(absl::string_view("")));
  EXPECT_TRUE(m4.Matches(absl::string_view()));
#endif  // GTEST_HAS_ABSL
            }

            TEST(MatchesRegexTest, CanDescribeSelf) {
                Matcher<const std::string> m1 = MatchesRegex(std::string("Hi.*"));
                EXPECT_EQ("matches regular expression \"Hi.*\"", Describe(m1));

                Matcher<const char *> m2 = MatchesRegex(new RE("a.*"));
                EXPECT_EQ("matches regular expression \"a.*\"", Describe(m2));

#if GTEST_HAS_ABSL
                                                                                                                                        Matcher<const absl::string_view> m3 = MatchesRegex(new RE("0.*"));
  EXPECT_EQ("matches regular expression \"0.*\"", Describe(m3));
#endif  // GTEST_HAS_ABSL
            }

// Tests ContainsRegex().

            TEST(ContainsRegexTest, MatchesStringContainingGivenRegex) {
                const Matcher<const char *> m1 = ContainsRegex(std::string("a.*z"));
                EXPECT_TRUE(m1.Matches("az"));
                EXPECT_TRUE(m1.Matches("0abcz1"));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const std::string &> m2 = ContainsRegex(new RE("a.*z"));
                EXPECT_TRUE(m2.Matches("azbz"));
                EXPECT_TRUE(m2.Matches("az1"));
                EXPECT_FALSE(m2.Matches("1a"));

#if GTEST_HAS_ABSL
                                                                                                                                        const Matcher<const absl::string_view&> m3 = ContainsRegex(new RE("a.*z"));
  EXPECT_TRUE(m3.Matches(absl::string_view("azbz")));
  EXPECT_TRUE(m3.Matches(absl::string_view("az1")));
  EXPECT_FALSE(m3.Matches(absl::string_view("1a")));
  EXPECT_FALSE(m3.Matches(absl::string_view()));
  const Matcher<const absl::string_view&> m4 = ContainsRegex("");
  EXPECT_TRUE(m4.Matches(absl::string_view("")));
  EXPECT_TRUE(m4.Matches(absl::string_view()));
#endif  // GTEST_HAS_ABSL
            }

            TEST(ContainsRegexTest, CanDescribeSelf) {
                Matcher<const std::string> m1 = ContainsRegex("Hi.*");
                EXPECT_EQ("contains regular expression \"Hi.*\"", Describe(m1));

                Matcher<const char *> m2 = ContainsRegex(new RE("a.*"));
                EXPECT_EQ("contains regular expression \"a.*\"", Describe(m2));

#if GTEST_HAS_ABSL
                                                                                                                                        Matcher<const absl::string_view> m3 = ContainsRegex(new RE("0.*"));
  EXPECT_EQ("contains regular expression \"0.*\"", Describe(m3));
#endif  // GTEST_HAS_ABSL
            }

// Tests for wide strings.
#if GTEST_HAS_STD_WSTRING
            TEST(StdWideStrEqTest, MatchesEqual) {
                Matcher<const wchar_t *> m = StrEq(::std::wstring(L"Hello"));
                EXPECT_TRUE(m.Matches(L"Hello"));
                EXPECT_FALSE(m.Matches(L"hello"));
                EXPECT_FALSE(m.Matches(nullptr));

                Matcher<const ::std::wstring &> m2 = StrEq(L"Hello");
                EXPECT_TRUE(m2.Matches(L"Hello"));
                EXPECT_FALSE(m2.Matches(L"Hi"));

                Matcher<const ::std::wstring &> m3 = StrEq(L"\xD3\x576\x8D3\xC74D");
                EXPECT_TRUE(m3.Matches(L"\xD3\x576\x8D3\xC74D"));
                EXPECT_FALSE(m3.Matches(L"\xD3\x576\x8D3\xC74E"));

                ::std::wstring str(L"01204500800");
                str[3] = L'\0';
                Matcher<const ::std::wstring &> m4 = StrEq(str);
                EXPECT_TRUE(m4.Matches(str));
                str[0] = str[6] = str[7] = str[9] = str[10] = L'\0';
                Matcher<const ::std::wstring &> m5 = StrEq(str);
                EXPECT_TRUE(m5.Matches(str));
            }

            TEST(StdWideStrEqTest, CanDescribeSelf) {
                Matcher<::std::wstring> m = StrEq(L"Hi-\'\"?\\\a\b\f\n\r\t\v");
                EXPECT_EQ("is equal to L\"Hi-\'\\\"?\\\\\\a\\b\\f\\n\\r\\t\\v\"",
                          Describe(m));

                Matcher<::std::wstring> m2 = StrEq(L"\xD3\x576\x8D3\xC74D");
                EXPECT_EQ("is equal to L\"\\xD3\\x576\\x8D3\\xC74D\"",
                          Describe(m2));

                ::std::wstring str(L"01204500800");
                str[3] = L'\0';
                Matcher<const ::std::wstring &> m4 = StrEq(str);
                EXPECT_EQ("is equal to L\"012\\04500800\"", Describe(m4));
                str[0] = str[6] = str[7] = str[9] = str[10] = L'\0';
                Matcher<const ::std::wstring &> m5 = StrEq(str);
                EXPECT_EQ("is equal to L\"\\012\\045\\0\\08\\0\\0\"", Describe(m5));
            }

            TEST(StdWideStrNeTest, MatchesUnequalString) {
                Matcher<const wchar_t *> m = StrNe(L"Hello");
                EXPECT_TRUE(m.Matches(L""));
                EXPECT_TRUE(m.Matches(nullptr));
                EXPECT_FALSE(m.Matches(L"Hello"));

                Matcher<::std::wstring> m2 = StrNe(::std::wstring(L"Hello"));
                EXPECT_TRUE(m2.Matches(L"hello"));
                EXPECT_FALSE(m2.Matches(L"Hello"));
            }

            TEST(StdWideStrNeTest, CanDescribeSelf) {
                Matcher<const wchar_t *> m = StrNe(L"Hi");
                EXPECT_EQ("isn't equal to L\"Hi\"", Describe(m));
            }

            TEST(StdWideStrCaseEqTest, MatchesEqualStringIgnoringCase) {
                Matcher<const wchar_t *> m = StrCaseEq(::std::wstring(L"Hello"));
                EXPECT_TRUE(m.Matches(L"Hello"));
                EXPECT_TRUE(m.Matches(L"hello"));
                EXPECT_FALSE(m.Matches(L"Hi"));
                EXPECT_FALSE(m.Matches(nullptr));

                Matcher<const ::std::wstring &> m2 = StrCaseEq(L"Hello");
                EXPECT_TRUE(m2.Matches(L"hello"));
                EXPECT_FALSE(m2.Matches(L"Hi"));
            }

            TEST(StdWideStrCaseEqTest, MatchesEqualStringWith0IgnoringCase) {
                ::std::wstring str1(L"oabocdooeoo");
                ::std::wstring str2(L"OABOCDOOEOO");
                Matcher<const ::std::wstring &> m0 = StrCaseEq(str1);
                EXPECT_FALSE(m0.Matches(str2 + ::std::wstring(1, L'\0')));

                str1[3] = str2[3] = L'\0';
                Matcher<const ::std::wstring &> m1 = StrCaseEq(str1);
                EXPECT_TRUE(m1.Matches(str2));

                str1[0] = str1[6] = str1[7] = str1[10] = L'\0';
                str2[0] = str2[6] = str2[7] = str2[10] = L'\0';
                Matcher<const ::std::wstring &> m2 = StrCaseEq(str1);
                str1[9] = str2[9] = L'\0';
                EXPECT_FALSE(m2.Matches(str2));

                Matcher<const ::std::wstring &> m3 = StrCaseEq(str1);
                EXPECT_TRUE(m3.Matches(str2));

                EXPECT_FALSE(m3.Matches(str2 + L"x"));
                str2.append(1, L'\0');
                EXPECT_FALSE(m3.Matches(str2));
                EXPECT_FALSE(m3.Matches(::std::wstring(str2, 0, 9)));
            }

            TEST(StdWideStrCaseEqTest, CanDescribeSelf) {
                Matcher<::std::wstring> m = StrCaseEq(L"Hi");
                EXPECT_EQ("is equal to (ignoring case) L\"Hi\"", Describe(m));
            }

            TEST(StdWideStrCaseNeTest, MatchesUnequalStringIgnoringCase) {
                Matcher<const wchar_t *> m = StrCaseNe(L"Hello");
                EXPECT_TRUE(m.Matches(L"Hi"));
                EXPECT_TRUE(m.Matches(nullptr));
                EXPECT_FALSE(m.Matches(L"Hello"));
                EXPECT_FALSE(m.Matches(L"hello"));

                Matcher<::std::wstring> m2 = StrCaseNe(::std::wstring(L"Hello"));
                EXPECT_TRUE(m2.Matches(L""));
                EXPECT_FALSE(m2.Matches(L"Hello"));
            }

            TEST(StdWideStrCaseNeTest, CanDescribeSelf) {
                Matcher<const wchar_t *> m = StrCaseNe(L"Hi");
                EXPECT_EQ("isn't equal to (ignoring case) L\"Hi\"", Describe(m));
            }

// Tests that HasSubstr() works for matching wstring-typed values.
            TEST(StdWideHasSubstrTest, WorksForStringClasses) {
                const Matcher<::std::wstring> m1 = HasSubstr(L"foo");
                EXPECT_TRUE(m1.Matches(::std::wstring(L"I love food.")));
                EXPECT_FALSE(m1.Matches(::std::wstring(L"tofo")));

                const Matcher<const ::std::wstring &> m2 = HasSubstr(L"foo");
                EXPECT_TRUE(m2.Matches(::std::wstring(L"I love food.")));
                EXPECT_FALSE(m2.Matches(::std::wstring(L"tofo")));
            }

// Tests that HasSubstr() works for matching C-wide-string-typed values.
            TEST(StdWideHasSubstrTest, WorksForCStrings) {
                const Matcher<wchar_t *> m1 = HasSubstr(L"foo");
                EXPECT_TRUE(m1.Matches(const_cast<wchar_t *>(L"I love food.")));
                EXPECT_FALSE(m1.Matches(const_cast<wchar_t *>(L"tofo")));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const wchar_t *> m2 = HasSubstr(L"foo");
                EXPECT_TRUE(m2.Matches(L"I love food."));
                EXPECT_FALSE(m2.Matches(L"tofo"));
                EXPECT_FALSE(m2.Matches(nullptr));
            }

// Tests that HasSubstr(s) describes itself properly.
            TEST(StdWideHasSubstrTest, CanDescribeSelf) {
                Matcher<::std::wstring> m = HasSubstr(L"foo\n\"");
                EXPECT_EQ("has substring L\"foo\\n\\\"\"", Describe(m));
            }

// Tests StartsWith(s).

            TEST(StdWideStartsWithTest, MatchesStringWithGivenPrefix) {
                const Matcher<const wchar_t *> m1 = StartsWith(::std::wstring(L""));
                EXPECT_TRUE(m1.Matches(L"Hi"));
                EXPECT_TRUE(m1.Matches(L""));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const ::std::wstring &> m2 = StartsWith(L"Hi");
                EXPECT_TRUE(m2.Matches(L"Hi"));
                EXPECT_TRUE(m2.Matches(L"Hi Hi!"));
                EXPECT_TRUE(m2.Matches(L"High"));
                EXPECT_FALSE(m2.Matches(L"H"));
                EXPECT_FALSE(m2.Matches(L" Hi"));
            }

            TEST(StdWideStartsWithTest, CanDescribeSelf) {
                Matcher<const ::std::wstring> m = StartsWith(L"Hi");
                EXPECT_EQ("starts with L\"Hi\"", Describe(m));
            }

// Tests EndsWith(s).

            TEST(StdWideEndsWithTest, MatchesStringWithGivenSuffix) {
                const Matcher<const wchar_t *> m1 = EndsWith(L"");
                EXPECT_TRUE(m1.Matches(L"Hi"));
                EXPECT_TRUE(m1.Matches(L""));
                EXPECT_FALSE(m1.Matches(nullptr));

                const Matcher<const ::std::wstring &> m2 = EndsWith(::std::wstring(L"Hi"));
                EXPECT_TRUE(m2.Matches(L"Hi"));
                EXPECT_TRUE(m2.Matches(L"Wow Hi Hi"));
                EXPECT_TRUE(m2.Matches(L"Super Hi"));
                EXPECT_FALSE(m2.Matches(L"i"));
                EXPECT_FALSE(m2.Matches(L"Hi "));
            }

            TEST(StdWideEndsWithTest, CanDescribeSelf) {
                Matcher<const ::std::wstring> m = EndsWith(L"Hi");
                EXPECT_EQ("ends with L\"Hi\"", Describe(m));
            }

#endif  // GTEST_HAS_STD_WSTRING

            typedef ::std::tuple<long, int> Tuple2;  // NOLINT

// Tests that Eq() matches a 2-tuple where the first field == the
// second field.
            TEST(Eq2Test, MatchesEqualArguments) {
                Matcher<const Tuple2 &> m = Eq();
                EXPECT_TRUE(m.Matches(Tuple2(5L, 5)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 6)));
            }

// Tests that Eq() describes itself properly.
            TEST(Eq2Test, CanDescribeSelf) {
                Matcher<const Tuple2 &> m = Eq();
                EXPECT_EQ("are an equal pair", Describe(m));
            }

// Tests that Ge() matches a 2-tuple where the first field >= the
// second field.
            TEST(Ge2Test, MatchesGreaterThanOrEqualArguments) {
                Matcher<const Tuple2 &> m = Ge();
                EXPECT_TRUE(m.Matches(Tuple2(5L, 4)));
                EXPECT_TRUE(m.Matches(Tuple2(5L, 5)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 6)));
            }

// Tests that Ge() describes itself properly.
            TEST(Ge2Test, CanDescribeSelf) {
                Matcher<const Tuple2 &> m = Ge();
                EXPECT_EQ("are a pair where the first >= the second", Describe(m));
            }

// Tests that Gt() matches a 2-tuple where the first field > the
// second field.
            TEST(Gt2Test, MatchesGreaterThanArguments) {
                Matcher<const Tuple2 &> m = Gt();
                EXPECT_TRUE(m.Matches(Tuple2(5L, 4)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 5)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 6)));
            }

// Tests that Gt() describes itself properly.
            TEST(Gt2Test, CanDescribeSelf) {
                Matcher<const Tuple2 &> m = Gt();
                EXPECT_EQ("are a pair where the first > the second", Describe(m));
            }

// Tests that Le() matches a 2-tuple where the first field <= the
// second field.
            TEST(Le2Test, MatchesLessThanOrEqualArguments) {
                Matcher<const Tuple2 &> m = Le();
                EXPECT_TRUE(m.Matches(Tuple2(5L, 6)));
                EXPECT_TRUE(m.Matches(Tuple2(5L, 5)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 4)));
            }

// Tests that Le() describes itself properly.
            TEST(Le2Test, CanDescribeSelf) {
                Matcher<const Tuple2 &> m = Le();
                EXPECT_EQ("are a pair where the first <= the second", Describe(m));
            }

// Tests that Lt() matches a 2-tuple where the first field < the
// second field.
            TEST(Lt2Test, MatchesLessThanArguments) {
                Matcher<const Tuple2 &> m = Lt();
                EXPECT_TRUE(m.Matches(Tuple2(5L, 6)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 5)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 4)));
            }

// Tests that Lt() describes itself properly.
            TEST(Lt2Test, CanDescribeSelf) {
                Matcher<const Tuple2 &> m = Lt();
                EXPECT_EQ("are a pair where the first < the second", Describe(m));
            }

// Tests that Ne() matches a 2-tuple where the first field != the
// second field.
            TEST(Ne2Test, MatchesUnequalArguments) {
                Matcher<const Tuple2 &> m = Ne();
                EXPECT_TRUE(m.Matches(Tuple2(5L, 6)));
                EXPECT_TRUE(m.Matches(Tuple2(5L, 4)));
                EXPECT_FALSE(m.Matches(Tuple2(5L, 5)));
            }

// Tests that Ne() describes itself properly.
            TEST(Ne2Test, CanDescribeSelf) {
                Matcher<const Tuple2 &> m = Ne();
                EXPECT_EQ("are an unequal pair", Describe(m));
            }

            TEST(PairMatchBaseTest, WorksWithMoveOnly) {
                using Pointers = std::tuple<std::unique_ptr<int>, std::unique_ptr<int>>;
                Matcher<Pointers> matcher = Eq();
                Pointers pointers;
                // Tested values don't matter; the point is that matcher does not copy the
                // matched values.
                EXPECT_TRUE(matcher.Matches(pointers));
            }

// Tests that FloatEq() matches a 2-tuple where
// FloatEq(first field) matches the second field.
            TEST(FloatEq2Test, MatchesEqualArguments) {
                typedef ::std::tuple<float, float> Tpl;
                Matcher<const Tpl &> m = FloatEq();
                EXPECT_TRUE(m.Matches(Tpl(1.0f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(0.3f, 0.1f + 0.1f + 0.1f)));
                EXPECT_FALSE(m.Matches(Tpl(1.1f, 1.0f)));
            }

// Tests that FloatEq() describes itself properly.
            TEST(FloatEq2Test, CanDescribeSelf) {
                Matcher<const ::std::tuple<float, float> &> m = FloatEq();
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that NanSensitiveFloatEq() matches a 2-tuple where
// NanSensitiveFloatEq(first field) matches the second field.
            TEST(NanSensitiveFloatEqTest, MatchesEqualArgumentsWithNaN) {
                typedef ::std::tuple<float, float> Tpl;
                Matcher<const Tpl &> m = NanSensitiveFloatEq();
                EXPECT_TRUE(m.Matches(Tpl(1.0f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(std::numeric_limits<float>::quiet_NaN(),
                                          std::numeric_limits<float>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(1.1f, 1.0f)));
                EXPECT_FALSE(m.Matches(Tpl(1.0f, std::numeric_limits<float>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(std::numeric_limits<float>::quiet_NaN(), 1.0f)));
            }

// Tests that NanSensitiveFloatEq() describes itself properly.
            TEST(NanSensitiveFloatEqTest, CanDescribeSelfWithNaNs) {
                Matcher<const ::std::tuple<float, float> &> m = NanSensitiveFloatEq();
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that DoubleEq() matches a 2-tuple where
// DoubleEq(first field) matches the second field.
            TEST(DoubleEq2Test, MatchesEqualArguments) {
                typedef ::std::tuple<double, double> Tpl;
                Matcher<const Tpl &> m = DoubleEq();
                EXPECT_TRUE(m.Matches(Tpl(1.0, 1.0)));
                EXPECT_TRUE(m.Matches(Tpl(0.3, 0.1 + 0.1 + 0.1)));
                EXPECT_FALSE(m.Matches(Tpl(1.1, 1.0)));
            }

// Tests that DoubleEq() describes itself properly.
            TEST(DoubleEq2Test, CanDescribeSelf) {
                Matcher<const ::std::tuple<double, double> &> m = DoubleEq();
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that NanSensitiveDoubleEq() matches a 2-tuple where
// NanSensitiveDoubleEq(first field) matches the second field.
            TEST(NanSensitiveDoubleEqTest, MatchesEqualArgumentsWithNaN) {
                typedef ::std::tuple<double, double> Tpl;
                Matcher<const Tpl &> m = NanSensitiveDoubleEq();
                EXPECT_TRUE(m.Matches(Tpl(1.0f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(std::numeric_limits<double>::quiet_NaN(),
                                          std::numeric_limits<double>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(1.1f, 1.0f)));
                EXPECT_FALSE(m.Matches(Tpl(1.0f, std::numeric_limits<double>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(std::numeric_limits<double>::quiet_NaN(), 1.0f)));
            }

// Tests that DoubleEq() describes itself properly.
            TEST(NanSensitiveDoubleEqTest, CanDescribeSelfWithNaNs) {
                Matcher<const ::std::tuple<double, double> &> m = NanSensitiveDoubleEq();
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that FloatEq() matches a 2-tuple where
// FloatNear(first field, max_abs_error) matches the second field.
            TEST(FloatNear2Test, MatchesEqualArguments) {
                typedef ::std::tuple<float, float> Tpl;
                Matcher<const Tpl &> m = FloatNear(0.5f);
                EXPECT_TRUE(m.Matches(Tpl(1.0f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(1.3f, 1.0f)));
                EXPECT_FALSE(m.Matches(Tpl(1.8f, 1.0f)));
            }

// Tests that FloatNear() describes itself properly.
            TEST(FloatNear2Test, CanDescribeSelf) {
                Matcher<const ::std::tuple<float, float> &> m = FloatNear(0.5f);
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that NanSensitiveFloatNear() matches a 2-tuple where
// NanSensitiveFloatNear(first field) matches the second field.
            TEST(NanSensitiveFloatNearTest, MatchesNearbyArgumentsWithNaN) {
                typedef ::std::tuple<float, float> Tpl;
                Matcher<const Tpl &> m = NanSensitiveFloatNear(0.5f);
                EXPECT_TRUE(m.Matches(Tpl(1.0f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(1.1f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(std::numeric_limits<float>::quiet_NaN(),
                                          std::numeric_limits<float>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(1.6f, 1.0f)));
                EXPECT_FALSE(m.Matches(Tpl(1.0f, std::numeric_limits<float>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(std::numeric_limits<float>::quiet_NaN(), 1.0f)));
            }

// Tests that NanSensitiveFloatNear() describes itself properly.
            TEST(NanSensitiveFloatNearTest, CanDescribeSelfWithNaNs) {
                Matcher<const ::std::tuple<float, float> &> m = NanSensitiveFloatNear(0.5f);
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that FloatEq() matches a 2-tuple where
// DoubleNear(first field, max_abs_error) matches the second field.
            TEST(DoubleNear2Test, MatchesEqualArguments) {
                typedef ::std::tuple<double, double> Tpl;
                Matcher<const Tpl &> m = DoubleNear(0.5);
                EXPECT_TRUE(m.Matches(Tpl(1.0, 1.0)));
                EXPECT_TRUE(m.Matches(Tpl(1.3, 1.0)));
                EXPECT_FALSE(m.Matches(Tpl(1.8, 1.0)));
            }

// Tests that DoubleNear() describes itself properly.
            TEST(DoubleNear2Test, CanDescribeSelf) {
                Matcher<const ::std::tuple<double, double> &> m = DoubleNear(0.5);
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that NanSensitiveDoubleNear() matches a 2-tuple where
// NanSensitiveDoubleNear(first field) matches the second field.
            TEST(NanSensitiveDoubleNearTest, MatchesNearbyArgumentsWithNaN) {
                typedef ::std::tuple<double, double> Tpl;
                Matcher<const Tpl &> m = NanSensitiveDoubleNear(0.5f);
                EXPECT_TRUE(m.Matches(Tpl(1.0f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(1.1f, 1.0f)));
                EXPECT_TRUE(m.Matches(Tpl(std::numeric_limits<double>::quiet_NaN(),
                                          std::numeric_limits<double>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(1.6f, 1.0f)));
                EXPECT_FALSE(m.Matches(Tpl(1.0f, std::numeric_limits<double>::quiet_NaN())));
                EXPECT_FALSE(m.Matches(Tpl(std::numeric_limits<double>::quiet_NaN(), 1.0f)));
            }

// Tests that NanSensitiveDoubleNear() describes itself properly.
            TEST(NanSensitiveDoubleNearTest, CanDescribeSelfWithNaNs) {
                Matcher<const ::std::tuple<double, double> &> m = NanSensitiveDoubleNear(0.5f);
                EXPECT_EQ("are an almost-equal pair", Describe(m));
            }

// Tests that Not(m) matches any value that doesn't match m.
            TEST(NotTest, NegatesMatcher) {
                Matcher<int> m;
                m = Not(Eq(2));
                EXPECT_TRUE(m.Matches(3));
                EXPECT_FALSE(m.Matches(2));
            }

// Tests that Not(m) describes itself properly.
            TEST(NotTest, CanDescribeSelf) {
                Matcher<int> m = Not(Eq(5));
                EXPECT_EQ("isn't equal to 5", Describe(m));
            }

// Tests that monomorphic matchers are safely cast by the Not matcher.
            TEST(NotTest, NotMatcherSafelyCastsMonomorphicMatchers) {
                // greater_than_5 is a monomorphic matcher.
                Matcher<int> greater_than_5 = Gt(5);

                Matcher<const int &> m = Not(greater_than_5);
                Matcher<int &> m2 = Not(greater_than_5);
                Matcher<int &> m3 = Not(m);
            }

// Helper to allow easy testing of AllOf matchers with num parameters.
            void AllOfMatches(int num, const Matcher<int> &m) {
                SCOPED_TRACE(Describe(m));
                EXPECT_TRUE(m.Matches(0));
                for (int i = 1; i <= num; ++i) {
                    EXPECT_FALSE(m.Matches(i));
                }
                EXPECT_TRUE(m.Matches(num + 1));
            }

// Tests that AllOf(m1, ..., mn) matches any value that matches all of
// the given matchers.
            TEST(AllOfTest, MatchesWhenAllMatch) {
                Matcher<int> m;
                m = AllOf(Le(2), Ge(1));
                EXPECT_TRUE(m.Matches(1));
                EXPECT_TRUE(m.Matches(2));
                EXPECT_FALSE(m.Matches(0));
                EXPECT_FALSE(m.Matches(3));

                m = AllOf(Gt(0), Ne(1), Ne(2));
                EXPECT_TRUE(m.Matches(3));
                EXPECT_FALSE(m.Matches(2));
                EXPECT_FALSE(m.Matches(1));
                EXPECT_FALSE(m.Matches(0));

                m = AllOf(Gt(0), Ne(1), Ne(2), Ne(3));
                EXPECT_TRUE(m.Matches(4));
                EXPECT_FALSE(m.Matches(3));
                EXPECT_FALSE(m.Matches(2));
                EXPECT_FALSE(m.Matches(1));
                EXPECT_FALSE(m.Matches(0));

                m = AllOf(Ge(0), Lt(10), Ne(3), Ne(5), Ne(7));
                EXPECT_TRUE(m.Matches(0));
                EXPECT_TRUE(m.Matches(1));
                EXPECT_FALSE(m.Matches(3));

                // The following tests for varying number of sub-matchers. Due to the way
                // the sub-matchers are handled it is enough to test every sub-matcher once
                // with sub-matchers using the same matcher type. Varying matcher types are
                // checked for above.
                AllOfMatches(2, AllOf(Ne(1), Ne(2)));
                AllOfMatches(3, AllOf(Ne(1), Ne(2), Ne(3)));
                AllOfMatches(4, AllOf(Ne(1), Ne(2), Ne(3), Ne(4)));
                AllOfMatches(5, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5)));
                AllOfMatches(6, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6)));
                AllOfMatches(7, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6), Ne(7)));
                AllOfMatches(8, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6), Ne(7),
                                      Ne(8)));
                AllOfMatches(9, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6), Ne(7),
                                      Ne(8), Ne(9)));
                AllOfMatches(10, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6), Ne(7), Ne(8),
                                       Ne(9), Ne(10)));
                AllOfMatches(
                        50, AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6), Ne(7), Ne(8), Ne(9),
                                  Ne(10), Ne(11), Ne(12), Ne(13), Ne(14), Ne(15), Ne(16), Ne(17),
                                  Ne(18), Ne(19), Ne(20), Ne(21), Ne(22), Ne(23), Ne(24), Ne(25),
                                  Ne(26), Ne(27), Ne(28), Ne(29), Ne(30), Ne(31), Ne(32), Ne(33),
                                  Ne(34), Ne(35), Ne(36), Ne(37), Ne(38), Ne(39), Ne(40), Ne(41),
                                  Ne(42), Ne(43), Ne(44), Ne(45), Ne(46), Ne(47), Ne(48), Ne(49),
                                  Ne(50)));
            }


// Tests that AllOf(m1, ..., mn) describes itself properly.
            TEST(AllOfTest, CanDescribeSelf) {
                Matcher<int> m;
                m = AllOf(Le(2), Ge(1));
                EXPECT_EQ("(is <= 2) and (is >= 1)", Describe(m));

                m = AllOf(Gt(0), Ne(1), Ne(2));
                std::string expected_descr1 =
                        "(is > 0) and (isn't equal to 1) and (isn't equal to 2)";
                EXPECT_EQ(expected_descr1, Describe(m));

                m = AllOf(Gt(0), Ne(1), Ne(2), Ne(3));
                std::string expected_descr2 =
                        "(is > 0) and (isn't equal to 1) and (isn't equal to 2) and (isn't equal "
                        "to 3)";
                EXPECT_EQ(expected_descr2, Describe(m));

                m = AllOf(Ge(0), Lt(10), Ne(3), Ne(5), Ne(7));
                std::string expected_descr3 =
                        "(is >= 0) and (is < 10) and (isn't equal to 3) and (isn't equal to 5) "
                        "and (isn't equal to 7)";
                EXPECT_EQ(expected_descr3, Describe(m));
            }

// Tests that AllOf(m1, ..., mn) describes its negation properly.
            TEST(AllOfTest, CanDescribeNegation) {
                Matcher<int> m;
                m = AllOf(Le(2), Ge(1));
                std::string expected_descr4 = "(isn't <= 2) or (isn't >= 1)";
                EXPECT_EQ(expected_descr4, DescribeNegation(m));

                m = AllOf(Gt(0), Ne(1), Ne(2));
                std::string expected_descr5 =
                        "(isn't > 0) or (is equal to 1) or (is equal to 2)";
                EXPECT_EQ(expected_descr5, DescribeNegation(m));

                m = AllOf(Gt(0), Ne(1), Ne(2), Ne(3));
                std::string expected_descr6 =
                        "(isn't > 0) or (is equal to 1) or (is equal to 2) or (is equal to 3)";
                EXPECT_EQ(expected_descr6, DescribeNegation(m));

                m = AllOf(Ge(0), Lt(10), Ne(3), Ne(5), Ne(7));
                std::string expected_desr7 =
                        "(isn't >= 0) or (isn't < 10) or (is equal to 3) or (is equal to 5) or "
                        "(is equal to 7)";
                EXPECT_EQ(expected_desr7, DescribeNegation(m));

                m = AllOf(Ne(1), Ne(2), Ne(3), Ne(4), Ne(5), Ne(6), Ne(7), Ne(8), Ne(9),
                          Ne(10), Ne(11));
                AllOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11);
                EXPECT_THAT(Describe(m), EndsWith("and (isn't equal to 11)"));
                AllOfMatches(11, m);
            }

// Tests that monomorphic matchers are safely cast by the AllOf matcher.
            TEST(AllOfTest, AllOfMatcherSafelyCastsMonomorphicMatchers) {
                // greater_than_5 and less_than_10 are monomorphic matchers.
                Matcher<int> greater_than_5 = Gt(5);
                Matcher<int> less_than_10 = Lt(10);

                Matcher<const int &> m = AllOf(greater_than_5, less_than_10);
                Matcher<int &> m2 = AllOf(greater_than_5, less_than_10);
                Matcher<int &> m3 = AllOf(greater_than_5, m2);

                // Tests that BothOf works when composing itself.
                Matcher<const int &> m4 = AllOf(greater_than_5, less_than_10, less_than_10);
                Matcher<int &> m5 = AllOf(greater_than_5, less_than_10, less_than_10);
            }

            TEST(AllOfTest, ExplainsResult) {
                Matcher<int> m;

                // Successful match.  Both matchers need to explain.  The second
                // matcher doesn't give an explanation, so only the first matcher's
                // explanation is printed.
                m = AllOf(GreaterThan(10), Lt(30));
                EXPECT_EQ("which is 15 more than 10", Explain(m, 25));

                // Successful match.  Both matchers need to explain.
                m = AllOf(GreaterThan(10), GreaterThan(20));
                EXPECT_EQ("which is 20 more than 10, and which is 10 more than 20",
                          Explain(m, 30));

                // Successful match.  All matchers need to explain.  The second
                // matcher doesn't given an explanation.
                m = AllOf(GreaterThan(10), Lt(30), GreaterThan(20));
                EXPECT_EQ("which is 15 more than 10, and which is 5 more than 20",
                          Explain(m, 25));

                // Successful match.  All matchers need to explain.
                m = AllOf(GreaterThan(10), GreaterThan(20), GreaterThan(30));
                EXPECT_EQ("which is 30 more than 10, and which is 20 more than 20, "
                          "and which is 10 more than 30",
                          Explain(m, 40));

                // Failed match.  The first matcher, which failed, needs to
                // explain.
                m = AllOf(GreaterThan(10), GreaterThan(20));
                EXPECT_EQ("which is 5 less than 10", Explain(m, 5));

                // Failed match.  The second matcher, which failed, needs to
                // explain.  Since it doesn't given an explanation, nothing is
                // printed.
                m = AllOf(GreaterThan(10), Lt(30));
                EXPECT_EQ("", Explain(m, 40));

                // Failed match.  The second matcher, which failed, needs to
                // explain.
                m = AllOf(GreaterThan(10), GreaterThan(20));
                EXPECT_EQ("which is 5 less than 20", Explain(m, 15));
            }

// Helper to allow easy testing of AnyOf matchers with num parameters.
            static void AnyOfMatches(int num, const Matcher<int> &m) {
                SCOPED_TRACE(Describe(m));
                EXPECT_FALSE(m.Matches(0));
                for (int i = 1; i <= num; ++i) {
                    EXPECT_TRUE(m.Matches(i));
                }
                EXPECT_FALSE(m.Matches(num + 1));
            }

            static void AnyOfStringMatches(int num, const Matcher<std::string> &m) {
                SCOPED_TRACE(Describe(m));
                EXPECT_FALSE(m.Matches(std::to_string(0)));

                for (int i = 1; i <= num; ++i) {
                    EXPECT_TRUE(m.Matches(std::to_string(i)));
                }
                EXPECT_FALSE(m.Matches(std::to_string(num + 1)));
            }

// Tests that AnyOf(m1, ..., mn) matches any value that matches at
// least one of the given matchers.
            TEST(AnyOfTest, MatchesWhenAnyMatches) {
                Matcher<int> m;
                m = AnyOf(Le(1), Ge(3));
                EXPECT_TRUE(m.Matches(1));
                EXPECT_TRUE(m.Matches(4));
                EXPECT_FALSE(m.Matches(2));

                m = AnyOf(Lt(0), Eq(1), Eq(2));
                EXPECT_TRUE(m.Matches(-1));
                EXPECT_TRUE(m.Matches(1));
                EXPECT_TRUE(m.Matches(2));
                EXPECT_FALSE(m.Matches(0));

                m = AnyOf(Lt(0), Eq(1), Eq(2), Eq(3));
                EXPECT_TRUE(m.Matches(-1));
                EXPECT_TRUE(m.Matches(1));
                EXPECT_TRUE(m.Matches(2));
                EXPECT_TRUE(m.Matches(3));
                EXPECT_FALSE(m.Matches(0));

                m = AnyOf(Le(0), Gt(10), 3, 5, 7);
                EXPECT_TRUE(m.Matches(0));
                EXPECT_TRUE(m.Matches(11));
                EXPECT_TRUE(m.Matches(3));
                EXPECT_FALSE(m.Matches(2));

                // The following tests for varying number of sub-matchers. Due to the way
                // the sub-matchers are handled it is enough to test every sub-matcher once
                // with sub-matchers using the same matcher type. Varying matcher types are
                // checked for above.
                AnyOfMatches(2, AnyOf(1, 2));
                AnyOfMatches(3, AnyOf(1, 2, 3));
                AnyOfMatches(4, AnyOf(1, 2, 3, 4));
                AnyOfMatches(5, AnyOf(1, 2, 3, 4, 5));
                AnyOfMatches(6, AnyOf(1, 2, 3, 4, 5, 6));
                AnyOfMatches(7, AnyOf(1, 2, 3, 4, 5, 6, 7));
                AnyOfMatches(8, AnyOf(1, 2, 3, 4, 5, 6, 7, 8));
                AnyOfMatches(9, AnyOf(1, 2, 3, 4, 5, 6, 7, 8, 9));
                AnyOfMatches(10, AnyOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
            }

// Tests the variadic version of the AnyOfMatcher.
            TEST(AnyOfTest, VariadicMatchesWhenAnyMatches) {
                // Also make sure AnyOf is defined in the right namespace and does not depend
                // on ADL.
                Matcher<int> m = ::testing::AnyOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11);

                EXPECT_THAT(Describe(m), EndsWith("or (is equal to 11)"));
                AnyOfMatches(11, m);
                AnyOfMatches(50, AnyOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
                                       11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
                                       21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
                                       31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
                                       41, 42, 43, 44, 45, 46, 47, 48, 49, 50));
                AnyOfStringMatches(
                        50, AnyOf("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12",
                                  "13", "14", "15", "16", "17", "18", "19", "20", "21", "22",
                                  "23", "24", "25", "26", "27", "28", "29", "30", "31", "32",
                                  "33", "34", "35", "36", "37", "38", "39", "40", "41", "42",
                                  "43", "44", "45", "46", "47", "48", "49", "50"));
            }

// Tests the variadic version of the ElementsAreMatcher
            TEST(ElementsAreTest, HugeMatcher) {
                vector<int> test_vector{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};

                EXPECT_THAT(test_vector,
                            ElementsAre(Eq(1), Eq(2), Lt(13), Eq(4), Eq(5), Eq(6), Eq(7),
                                        Eq(8), Eq(9), Eq(10), Gt(1), Eq(12)));
            }

// Tests the variadic version of the UnorderedElementsAreMatcher
            TEST(ElementsAreTest, HugeMatcherStr) {
                vector<std::string> test_vector{
                        "literal_string", "", "", "", "", "", "", "", "", "", "", ""};

                EXPECT_THAT(test_vector, UnorderedElementsAre("literal_string", _, _, _, _, _,
                                                              _, _, _, _, _, _));
            }

// Tests the variadic version of the UnorderedElementsAreMatcher
            TEST(ElementsAreTest, HugeMatcherUnordered) {
                vector<int> test_vector{2, 1, 8, 5, 4, 6, 7, 3, 9, 12, 11, 10};

                EXPECT_THAT(test_vector, UnorderedElementsAre(
                        Eq(2), Eq(1), Gt(7), Eq(5), Eq(4), Eq(6), Eq(7),
                        Eq(3), Eq(9), Eq(12), Eq(11), Ne(122)));
            }


// Tests that AnyOf(m1, ..., mn) describes itself properly.
            TEST(AnyOfTest, CanDescribeSelf) {
                Matcher<int> m;
                m = AnyOf(Le(1), Ge(3));

                EXPECT_EQ("(is <= 1) or (is >= 3)",
                          Describe(m));

                m = AnyOf(Lt(0), Eq(1), Eq(2));
                EXPECT_EQ("(is < 0) or (is equal to 1) or (is equal to 2)", Describe(m));

                m = AnyOf(Lt(0), Eq(1), Eq(2), Eq(3));
                EXPECT_EQ("(is < 0) or (is equal to 1) or (is equal to 2) or (is equal to 3)",
                          Describe(m));

                m = AnyOf(Le(0), Gt(10), 3, 5, 7);
                EXPECT_EQ(
                        "(is <= 0) or (is > 10) or (is equal to 3) or (is equal to 5) or (is "
                        "equal to 7)",
                        Describe(m));
            }

// Tests that AnyOf(m1, ..., mn) describes its negation properly.
            TEST(AnyOfTest, CanDescribeNegation) {
                Matcher<int> m;
                m = AnyOf(Le(1), Ge(3));
                EXPECT_EQ("(isn't <= 1) and (isn't >= 3)",
                          DescribeNegation(m));

                m = AnyOf(Lt(0), Eq(1), Eq(2));
                EXPECT_EQ("(isn't < 0) and (isn't equal to 1) and (isn't equal to 2)",
                          DescribeNegation(m));

                m = AnyOf(Lt(0), Eq(1), Eq(2), Eq(3));
                EXPECT_EQ(
                        "(isn't < 0) and (isn't equal to 1) and (isn't equal to 2) and (isn't "
                        "equal to 3)",
                        DescribeNegation(m));

                m = AnyOf(Le(0), Gt(10), 3, 5, 7);
                EXPECT_EQ(
                        "(isn't <= 0) and (isn't > 10) and (isn't equal to 3) and (isn't equal "
                        "to 5) and (isn't equal to 7)",
                        DescribeNegation(m));
            }

// Tests that monomorphic matchers are safely cast by the AnyOf matcher.
            TEST(AnyOfTest, AnyOfMatcherSafelyCastsMonomorphicMatchers) {
                // greater_than_5 and less_than_10 are monomorphic matchers.
                Matcher<int> greater_than_5 = Gt(5);
                Matcher<int> less_than_10 = Lt(10);

                Matcher<const int &> m = AnyOf(greater_than_5, less_than_10);
                Matcher<int &> m2 = AnyOf(greater_than_5, less_than_10);
                Matcher<int &> m3 = AnyOf(greater_than_5, m2);

                // Tests that EitherOf works when composing itself.
                Matcher<const int &> m4 = AnyOf(greater_than_5, less_than_10, less_than_10);
                Matcher<int &> m5 = AnyOf(greater_than_5, less_than_10, less_than_10);
            }

            TEST(AnyOfTest, ExplainsResult) {
                Matcher<int> m;

                // Failed match.  Both matchers need to explain.  The second
                // matcher doesn't give an explanation, so only the first matcher's
                // explanation is printed.
                m = AnyOf(GreaterThan(10), Lt(0));
                EXPECT_EQ("which is 5 less than 10", Explain(m, 5));

                // Failed match.  Both matchers need to explain.
                m = AnyOf(GreaterThan(10), GreaterThan(20));
                EXPECT_EQ("which is 5 less than 10, and which is 15 less than 20",
                          Explain(m, 5));

                // Failed match.  All matchers need to explain.  The second
                // matcher doesn't given an explanation.
                m = AnyOf(GreaterThan(10), Gt(20), GreaterThan(30));
                EXPECT_EQ("which is 5 less than 10, and which is 25 less than 30",
                          Explain(m, 5));

                // Failed match.  All matchers need to explain.
                m = AnyOf(GreaterThan(10), GreaterThan(20), GreaterThan(30));
                EXPECT_EQ("which is 5 less than 10, and which is 15 less than 20, "
                          "and which is 25 less than 30",
                          Explain(m, 5));

                // Successful match.  The first matcher, which succeeded, needs to
                // explain.
                m = AnyOf(GreaterThan(10), GreaterThan(20));
                EXPECT_EQ("which is 5 more than 10", Explain(m, 15));

                // Successful match.  The second matcher, which succeeded, needs to
                // explain.  Since it doesn't given an explanation, nothing is
                // printed.
                m = AnyOf(GreaterThan(10), Lt(30));
                EXPECT_EQ("", Explain(m, 0));

                // Successful match.  The second matcher, which succeeded, needs to
                // explain.
                m = AnyOf(GreaterThan(30), GreaterThan(20));
                EXPECT_EQ("which is 5 more than 20", Explain(m, 25));
            }

// The following predicate function and predicate functor are for
// testing the Truly(predicate) matcher.

// Returns non-zero if the input is positive.  Note that the return
// type of this function is not bool.  It's OK as Truly() accepts any
// unary function or functor whose return type can be implicitly
// converted to bool.
            int IsPositive(double x) {
                return x > 0 ? 1 : 0;
            }

// This functor returns true if the input is greater than the given
// number.
            class IsGreaterThan {
            public:
                explicit IsGreaterThan(int threshold) : threshold_(threshold) {}

                bool operator()(int n) const { return n > threshold_; }

            private:
                int threshold_;
            };

// For testing Truly().
            const int foo = 0;

// This predicate returns true if and only if the argument references foo and
// has a zero value.
            bool ReferencesFooAndIsZero(const int &n) {
                return (&n == &foo) && (n == 0);
            }

// Tests that Truly(predicate) matches what satisfies the given
// predicate.
            TEST(TrulyTest, MatchesWhatSatisfiesThePredicate) {
                Matcher<double> m = Truly(IsPositive);
                EXPECT_TRUE(m.Matches(2.0));
                EXPECT_FALSE(m.Matches(-1.5));
            }

// Tests that Truly(predicate_functor) works too.
            TEST(TrulyTest, CanBeUsedWithFunctor) {
                Matcher<int> m = Truly(IsGreaterThan(5));
                EXPECT_TRUE(m.Matches(6));
                EXPECT_FALSE(m.Matches(4));
            }

// A class that can be implicitly converted to bool.
            class ConvertibleToBool {
            public:
                explicit ConvertibleToBool(int number) : number_(number) {}

                operator bool() const { return number_ != 0; }

            private:
                int number_;
            };

            ConvertibleToBool IsNotZero(int number) {
                return ConvertibleToBool(number);
            }

// Tests that the predicate used in Truly() may return a class that's
// implicitly convertible to bool, even when the class has no
// operator!().
            TEST(TrulyTest, PredicateCanReturnAClassConvertibleToBool) {
                Matcher<int> m = Truly(IsNotZero);
                EXPECT_TRUE(m.Matches(1));
                EXPECT_FALSE(m.Matches(0));
            }

// Tests that Truly(predicate) can describe itself properly.
            TEST(TrulyTest, CanDescribeSelf) {
                Matcher<double> m = Truly(IsPositive);
                EXPECT_EQ("satisfies the given predicate",
                          Describe(m));
            }

// Tests that Truly(predicate) works when the matcher takes its
// argument by reference.
            TEST(TrulyTest, WorksForByRefArguments) {
                Matcher<const int &> m = Truly(ReferencesFooAndIsZero);
                EXPECT_TRUE(m.Matches(foo));
                int n = 0;
                EXPECT_FALSE(m.Matches(n));
            }

// Tests that Matches(m) is a predicate satisfied by whatever that
// matches matcher m.
            TEST(MatchesTest, IsSatisfiedByWhatMatchesTheMatcher) {
                EXPECT_TRUE(Matches(Ge(0))(1));
                EXPECT_FALSE(Matches(Eq('a'))('b'));
            }

// Tests that Matches(m) works when the matcher takes its argument by
// reference.
            TEST(MatchesTest, WorksOnByRefArguments) {
                int m = 0, n = 0;
                EXPECT_TRUE(Matches(AllOf(Ref(n), Eq(0)))(n));
                EXPECT_FALSE(Matches(Ref(m))(n));
            }

// Tests that a Matcher on non-reference type can be used in
// Matches().
            TEST(MatchesTest, WorksWithMatcherOnNonRefType) {
                Matcher<int> eq5 = Eq(5);
                EXPECT_TRUE(Matches(eq5)(5));
                EXPECT_FALSE(Matches(eq5)(2));
            }

// Tests Value(value, matcher).  Since Value() is a simple wrapper for
// Matches(), which has been tested already, we don't spend a lot of
// effort on testing Value().
            TEST(ValueTest, WorksWithPolymorphicMatcher) {
                EXPECT_TRUE(Value("hi", StartsWith("h")));
                EXPECT_FALSE(Value(5, Gt(10)));
            }

            TEST(ValueTest, WorksWithMonomorphicMatcher) {
                const Matcher<int> is_zero = Eq(0);
                EXPECT_TRUE(Value(0, is_zero));
                EXPECT_FALSE(Value('a', is_zero));

                int n = 0;
                const Matcher<const int &> ref_n = Ref(n);
                EXPECT_TRUE(Value(n, ref_n));
                EXPECT_FALSE(Value(1, ref_n));
            }

            TEST(ExplainMatchResultTest, WorksWithPolymorphicMatcher) {
                StringMatchResultListener listener1;
                EXPECT_TRUE(ExplainMatchResult(PolymorphicIsEven(), 42, &listener1));
                EXPECT_EQ("% 2 == 0", listener1.str());

                StringMatchResultListener listener2;
                EXPECT_FALSE(ExplainMatchResult(Ge(42), 1.5, &listener2));
                EXPECT_EQ("", listener2.str());
            }

            TEST(ExplainMatchResultTest, WorksWithMonomorphicMatcher) {
                const Matcher<int> is_even = PolymorphicIsEven();
                StringMatchResultListener listener1;
                EXPECT_TRUE(ExplainMatchResult(is_even, 42, &listener1));
                EXPECT_EQ("% 2 == 0", listener1.str());

                const Matcher<const double &> is_zero = Eq(0);
                StringMatchResultListener listener2;
                EXPECT_FALSE(ExplainMatchResult(is_zero, 1.5, &listener2));
                EXPECT_EQ("", listener2.str());
            }

            MATCHER_P(Really, inner_matcher, "") {
                return ExplainMatchResult(inner_matcher, arg, result_listener);
            }

            TEST(ExplainMatchResultTest, WorksInsideMATCHER) {
                EXPECT_THAT(0, Really(Eq(0)));
            }

            TEST(DescribeMatcherTest, WorksWithValue) {
                EXPECT_EQ("is equal to 42", DescribeMatcher<int>(42));
                EXPECT_EQ("isn't equal to 42", DescribeMatcher<int>(42, true));
            }

            TEST(DescribeMatcherTest, WorksWithMonomorphicMatcher) {
                const Matcher<int> monomorphic = Le(0);
                EXPECT_EQ("is <= 0", DescribeMatcher<int>(monomorphic));
                EXPECT_EQ("isn't <= 0", DescribeMatcher<int>(monomorphic, true));
            }

            TEST(DescribeMatcherTest, WorksWithPolymorphicMatcher) {
                EXPECT_EQ("is even", DescribeMatcher<int>(PolymorphicIsEven()));
                EXPECT_EQ("is odd", DescribeMatcher<int>(PolymorphicIsEven(), true));
            }

            TEST(AllArgsTest, WorksForTuple) {
                EXPECT_THAT(std::make_tuple(1, 2L), AllArgs(Lt()));
                EXPECT_THAT(std::make_tuple(2L, 1), Not(AllArgs(Lt())));
            }

            TEST(AllArgsTest, WorksForNonTuple) {
                EXPECT_THAT(42, AllArgs(Gt(0)));
                EXPECT_THAT('a', Not(AllArgs(Eq('b'))));
            }

            class AllArgsHelper {
            public:
                AllArgsHelper() {}

                MOCK_METHOD2(Helper, int(char x, int y));

            private:
                GTEST_DISALLOW_COPY_AND_ASSIGN_(AllArgsHelper);
            };

            TEST(AllArgsTest, WorksInWithClause) {
                AllArgsHelper helper;
                ON_CALL(helper, Helper(_, _))
                        .With(AllArgs(Lt()))
                        .WillByDefault(Return(1));
                EXPECT_CALL(helper, Helper(_, _));
                EXPECT_CALL(helper, Helper(_, _))
                        .With(AllArgs(Gt()))
                        .WillOnce(Return(2));

                EXPECT_EQ(1, helper.Helper('\1', 2));
                EXPECT_EQ(2, helper.Helper('a', 1));
            }

            class OptionalMatchersHelper {
            public:
                OptionalMatchersHelper() {}

                MOCK_METHOD0(NoArgs, int());

                MOCK_METHOD1(OneArg, int(int y));

                MOCK_METHOD2(TwoArgs, int(char x, int y));

                MOCK_METHOD1(Overloaded, int(char x));
                MOCK_METHOD2(Overloaded, int(char x, int y));

            private:
                GTEST_DISALLOW_COPY_AND_ASSIGN_(OptionalMatchersHelper);
            };

            TEST(AllArgsTest, WorksWithoutMatchers) {
                OptionalMatchersHelper helper;

                ON_CALL(helper, NoArgs).WillByDefault(Return(10));
                ON_CALL(helper, OneArg).WillByDefault(Return(20));
                ON_CALL(helper, TwoArgs).WillByDefault(Return(30));

                EXPECT_EQ(10, helper.NoArgs());
                EXPECT_EQ(20, helper.OneArg(1));
                EXPECT_EQ(30, helper.TwoArgs('\1', 2));

                EXPECT_CALL(helper, NoArgs).Times(1);
                EXPECT_CALL(helper, OneArg).WillOnce(Return(100));
                EXPECT_CALL(helper, OneArg(17)).WillOnce(Return(200));
                EXPECT_CALL(helper, TwoArgs).Times(0);

                EXPECT_EQ(10, helper.NoArgs());
                EXPECT_EQ(100, helper.OneArg(1));
                EXPECT_EQ(200, helper.OneArg(17));
            }

// Tests that ASSERT_THAT() and EXPECT_THAT() work when the value
// matches the matcher.
            TEST(MatcherAssertionTest, WorksWhenMatcherIsSatisfied) {
                ASSERT_THAT(5, Ge(2)) << "This should succeed.";
                ASSERT_THAT("Foo", EndsWith("oo"));
                EXPECT_THAT(2, AllOf(Le(7), Ge(0))) << "This should succeed too.";
                EXPECT_THAT("Hello", StartsWith("Hell"));
            }

// Tests that ASSERT_THAT() and EXPECT_THAT() work when the value
// doesn't match the matcher.
            TEST(MatcherAssertionTest, WorksWhenMatcherIsNotSatisfied) {
                // 'n' must be static as it is used in an EXPECT_FATAL_FAILURE(),
                // which cannot reference auto variables.
                static unsigned short n;  // NOLINT
                n = 5;

                // VC++ prior to version 8.0 SP1 has a bug where it will not see any
                // functions declared in the namespace scope from within nested classes.
                // EXPECT/ASSERT_(NON)FATAL_FAILURE macros use nested classes so that all
                // namespace-level functions invoked inside them need to be explicitly
                // resolved.
                EXPECT_FATAL_FAILURE(ASSERT_THAT(n, ::testing::Gt(10)),
                                     "Value of: n\n"
                                     "Expected: is > 10\n"
                                     "  Actual: 5" + OfType("unsigned short"));
                n = 0;
                EXPECT_NONFATAL_FAILURE(
                        EXPECT_THAT(n, ::testing::AllOf(::testing::Le(7), ::testing::Ge(5))),
                        "Value of: n\n"
                        "Expected: (is <= 7) and (is >= 5)\n"
                        "  Actual: 0" + OfType("unsigned short"));
            }

// Tests that ASSERT_THAT() and EXPECT_THAT() work when the argument
// has a reference type.
            TEST(MatcherAssertionTest, WorksForByRefArguments) {
                // We use a static variable here as EXPECT_FATAL_FAILURE() cannot
                // reference auto variables.
                static int n;
                n = 0;
                EXPECT_THAT(n, AllOf(Le(7), Ref(n)));
                EXPECT_FATAL_FAILURE(ASSERT_THAT(n, ::testing::Not(::testing::Ref(n))),
                                     "Value of: n\n"
                                     "Expected: does not reference the variable @");
                // Tests the "Actual" part.
                EXPECT_FATAL_FAILURE(ASSERT_THAT(n, ::testing::Not(::testing::Ref(n))),
                                     "Actual: 0" + OfType("int") + ", which is located @");
            }

// Tests that ASSERT_THAT() and EXPECT_THAT() work when the matcher is
// monomorphic.
            TEST(MatcherAssertionTest, WorksForMonomorphicMatcher) {
                Matcher<const char *> starts_with_he = StartsWith("he");
                ASSERT_THAT("hello", starts_with_he);

                Matcher<const std::string &> ends_with_ok = EndsWith("ok");
                ASSERT_THAT("book", ends_with_ok);
                const std::string bad = "bad";
                EXPECT_NONFATAL_FAILURE(EXPECT_THAT(bad, ends_with_ok),
                                        "Value of: bad\n"
                                        "Expected: ends with \"ok\"\n"
                                        "  Actual: \"bad\"");
                Matcher<int> is_greater_than_5 = Gt(5);
                EXPECT_NONFATAL_FAILURE(EXPECT_THAT(5, is_greater_than_5),
                                        "Value of: 5\n"
                                        "Expected: is > 5\n"
                                        "  Actual: 5" + OfType("int"));
            }

// Tests floating-point matchers.
            template<typename RawType>
            class FloatingPointTest : public testing::Test {
            protected:
                typedef testing::internal::FloatingPoint<RawType> Floating;
                typedef typename Floating::Bits Bits;

                FloatingPointTest()
                        : max_ulps_(Floating::kMaxUlps),
                          zero_bits_(Floating(0).bits()),
                          one_bits_(Floating(1).bits()),
                          infinity_bits_(Floating(Floating::Infinity()).bits()),
                          close_to_positive_zero_(
                                  Floating::ReinterpretBits(zero_bits_ + max_ulps_ / 2)),
                          close_to_negative_zero_(
                                  -Floating::ReinterpretBits(zero_bits_ + max_ulps_ - max_ulps_ / 2)),
                          further_from_negative_zero_(-Floating::ReinterpretBits(
                                  zero_bits_ + max_ulps_ + 1 - max_ulps_ / 2)),
                          close_to_one_(Floating::ReinterpretBits(one_bits_ + max_ulps_)),
                          further_from_one_(Floating::ReinterpretBits(one_bits_ + max_ulps_ + 1)),
                          infinity_(Floating::Infinity()),
                          close_to_infinity_(
                                  Floating::ReinterpretBits(infinity_bits_ - max_ulps_)),
                          further_from_infinity_(
                                  Floating::ReinterpretBits(infinity_bits_ - max_ulps_ - 1)),
                          max_(Floating::Max()),
                          nan1_(Floating::ReinterpretBits(Floating::kExponentBitMask | 1)),
                          nan2_(Floating::ReinterpretBits(Floating::kExponentBitMask | 200)) {
                }

                void TestSize() {
                    EXPECT_EQ(sizeof(RawType), sizeof(Bits));
                }

                // A battery of tests for FloatingEqMatcher::Matches.
                // matcher_maker is a pointer to a function which creates a FloatingEqMatcher.
                void TestMatches(
                        testing::internal::FloatingEqMatcher<RawType> (*matcher_maker)(RawType)) {
                    Matcher<RawType> m1 = matcher_maker(0.0);
                    EXPECT_TRUE(m1.Matches(-0.0));
                    EXPECT_TRUE(m1.Matches(close_to_positive_zero_));
                    EXPECT_TRUE(m1.Matches(close_to_negative_zero_));
                    EXPECT_FALSE(m1.Matches(1.0));

                    Matcher<RawType> m2 = matcher_maker(close_to_positive_zero_);
                    EXPECT_FALSE(m2.Matches(further_from_negative_zero_));

                    Matcher<RawType> m3 = matcher_maker(1.0);
                    EXPECT_TRUE(m3.Matches(close_to_one_));
                    EXPECT_FALSE(m3.Matches(further_from_one_));

                    // Test commutativity: matcher_maker(0.0).Matches(1.0) was tested above.
                    EXPECT_FALSE(m3.Matches(0.0));

                    Matcher<RawType> m4 = matcher_maker(-infinity_);
                    EXPECT_TRUE(m4.Matches(-close_to_infinity_));

                    Matcher<RawType> m5 = matcher_maker(infinity_);
                    EXPECT_TRUE(m5.Matches(close_to_infinity_));

                    // This is interesting as the representations of infinity_ and nan1_
                    // are only 1 DLP apart.
                    EXPECT_FALSE(m5.Matches(nan1_));

                    // matcher_maker can produce a Matcher<const RawType&>, which is needed in
                    // some cases.
                    Matcher<const RawType &> m6 = matcher_maker(0.0);
                    EXPECT_TRUE(m6.Matches(-0.0));
                    EXPECT_TRUE(m6.Matches(close_to_positive_zero_));
                    EXPECT_FALSE(m6.Matches(1.0));

                    // matcher_maker can produce a Matcher<RawType&>, which is needed in some
                    // cases.
                    Matcher<RawType &> m7 = matcher_maker(0.0);
                    RawType x = 0.0;
                    EXPECT_TRUE(m7.Matches(x));
                    x = 0.01f;
                    EXPECT_FALSE(m7.Matches(x));
                }

                // Pre-calculated numbers to be used by the tests.

                const Bits max_ulps_;

                const Bits zero_bits_;  // The bits that represent 0.0.
                const Bits one_bits_;  // The bits that represent 1.0.
                const Bits infinity_bits_;  // The bits that represent +infinity.

                // Some numbers close to 0.0.
                const RawType close_to_positive_zero_;
                const RawType close_to_negative_zero_;
                const RawType further_from_negative_zero_;

                // Some numbers close to 1.0.
                const RawType close_to_one_;
                const RawType further_from_one_;

                // Some numbers close to +infinity.
                const RawType infinity_;
                const RawType close_to_infinity_;
                const RawType further_from_infinity_;

                // Maximum representable value that's not infinity.
                const RawType max_;

                // Some NaNs.
                const RawType nan1_;
                const RawType nan2_;
            };

// Tests floating-point matchers with fixed epsilons.
            template<typename RawType>
            class FloatingPointNearTest : public FloatingPointTest<RawType> {
            protected:
                typedef FloatingPointTest<RawType> ParentType;

                // A battery of tests for FloatingEqMatcher::Matches with a fixed epsilon.
                // matcher_maker is a pointer to a function which creates a FloatingEqMatcher.
                void TestNearMatches(
                        testing::internal::FloatingEqMatcher<RawType>
                        (*matcher_maker)(RawType, RawType)) {
                    Matcher<RawType> m1 = matcher_maker(0.0, 0.0);
                    EXPECT_TRUE(m1.Matches(0.0));
                    EXPECT_TRUE(m1.Matches(-0.0));
                    EXPECT_FALSE(m1.Matches(ParentType::close_to_positive_zero_));
                    EXPECT_FALSE(m1.Matches(ParentType::close_to_negative_zero_));
                    EXPECT_FALSE(m1.Matches(1.0));

                    Matcher<RawType> m2 = matcher_maker(0.0, 1.0);
                    EXPECT_TRUE(m2.Matches(0.0));
                    EXPECT_TRUE(m2.Matches(-0.0));
                    EXPECT_TRUE(m2.Matches(1.0));
                    EXPECT_TRUE(m2.Matches(-1.0));
                    EXPECT_FALSE(m2.Matches(ParentType::close_to_one_));
                    EXPECT_FALSE(m2.Matches(-ParentType::close_to_one_));

                    // Check that inf matches inf, regardless of the of the specified max
                    // absolute error.
                    Matcher<RawType> m3 = matcher_maker(ParentType::infinity_, 0.0);
                    EXPECT_TRUE(m3.Matches(ParentType::infinity_));
                    EXPECT_FALSE(m3.Matches(ParentType::close_to_infinity_));
                    EXPECT_FALSE(m3.Matches(-ParentType::infinity_));

                    Matcher<RawType> m4 = matcher_maker(-ParentType::infinity_, 0.0);
                    EXPECT_TRUE(m4.Matches(-ParentType::infinity_));
                    EXPECT_FALSE(m4.Matches(-ParentType::close_to_infinity_));
                    EXPECT_FALSE(m4.Matches(ParentType::infinity_));

                    // Test various overflow scenarios.
                    Matcher<RawType> m5 = matcher_maker(ParentType::max_, ParentType::max_);
                    EXPECT_TRUE(m5.Matches(ParentType::max_));
                    EXPECT_FALSE(m5.Matches(-ParentType::max_));

                    Matcher<RawType> m6 = matcher_maker(-ParentType::max_, ParentType::max_);
                    EXPECT_FALSE(m6.Matches(ParentType::max_));
                    EXPECT_TRUE(m6.Matches(-ParentType::max_));

                    Matcher<RawType> m7 = matcher_maker(ParentType::max_, 0);
                    EXPECT_TRUE(m7.Matches(ParentType::max_));
                    EXPECT_FALSE(m7.Matches(-ParentType::max_));

                    Matcher<RawType> m8 = matcher_maker(-ParentType::max_, 0);
                    EXPECT_FALSE(m8.Matches(ParentType::max_));
                    EXPECT_TRUE(m8.Matches(-ParentType::max_));

                    // The difference between max() and -max() normally overflows to infinity,
                    // but it should still match if the max_abs_error is also infinity.
                    Matcher<RawType> m9 = matcher_maker(
                            ParentType::max_, ParentType::infinity_);
                    EXPECT_TRUE(m8.Matches(-ParentType::max_));

                    // matcher_maker can produce a Matcher<const RawType&>, which is needed in
                    // some cases.
                    Matcher<const RawType &> m10 = matcher_maker(0.0, 1.0);
                    EXPECT_TRUE(m10.Matches(-0.0));
                    EXPECT_TRUE(m10.Matches(ParentType::close_to_positive_zero_));
                    EXPECT_FALSE(m10.Matches(ParentType::close_to_one_));

                    // matcher_maker can produce a Matcher<RawType&>, which is needed in some
                    // cases.
                    Matcher<RawType &> m11 = matcher_maker(0.0, 1.0);
                    RawType x = 0.0;
                    EXPECT_TRUE(m11.Matches(x));
                    x = 1.0f;
                    EXPECT_TRUE(m11.Matches(x));
                    x = -1.0f;
                    EXPECT_TRUE(m11.Matches(x));
                    x = 1.1f;
                    EXPECT_FALSE(m11.Matches(x));
                    x = -1.1f;
                    EXPECT_FALSE(m11.Matches(x));
                }
            };

// Instantiate FloatingPointTest for testing floats.
            typedef FloatingPointTest<float> FloatTest;

            TEST_F(FloatTest, FloatEqApproximatelyMatchesFloats) {
                TestMatches(&FloatEq);
            }

            TEST_F(FloatTest, NanSensitiveFloatEqApproximatelyMatchesFloats) {
                TestMatches(&NanSensitiveFloatEq);
            }

            TEST_F(FloatTest, FloatEqCannotMatchNaN) {
                // FloatEq never matches NaN.
                Matcher<float> m = FloatEq(nan1_);
                EXPECT_FALSE(m.Matches(nan1_));
                EXPECT_FALSE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST_F(FloatTest, NanSensitiveFloatEqCanMatchNaN) {
                // NanSensitiveFloatEq will match NaN.
                Matcher<float> m = NanSensitiveFloatEq(nan1_);
                EXPECT_TRUE(m.Matches(nan1_));
                EXPECT_TRUE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST_F(FloatTest, FloatEqCanDescribeSelf) {
                Matcher<float> m1 = FloatEq(2.0f);
                EXPECT_EQ("is approximately 2", Describe(m1));
                EXPECT_EQ("isn't approximately 2", DescribeNegation(m1));

                Matcher<float> m2 = FloatEq(0.5f);
                EXPECT_EQ("is approximately 0.5", Describe(m2));
                EXPECT_EQ("isn't approximately 0.5", DescribeNegation(m2));

                Matcher<float> m3 = FloatEq(nan1_);
                EXPECT_EQ("never matches", Describe(m3));
                EXPECT_EQ("is anything", DescribeNegation(m3));
            }

            TEST_F(FloatTest, NanSensitiveFloatEqCanDescribeSelf) {
                Matcher<float> m1 = NanSensitiveFloatEq(2.0f);
                EXPECT_EQ("is approximately 2", Describe(m1));
                EXPECT_EQ("isn't approximately 2", DescribeNegation(m1));

                Matcher<float> m2 = NanSensitiveFloatEq(0.5f);
                EXPECT_EQ("is approximately 0.5", Describe(m2));
                EXPECT_EQ("isn't approximately 0.5", DescribeNegation(m2));

                Matcher<float> m3 = NanSensitiveFloatEq(nan1_);
                EXPECT_EQ("is NaN", Describe(m3));
                EXPECT_EQ("isn't NaN", DescribeNegation(m3));
            }

// Instantiate FloatingPointTest for testing floats with a user-specified
// max absolute error.
            typedef FloatingPointNearTest<float> FloatNearTest;

            TEST_F(FloatNearTest, FloatNearMatches) {
                TestNearMatches(&FloatNear);
            }

            TEST_F(FloatNearTest, NanSensitiveFloatNearApproximatelyMatchesFloats) {
                TestNearMatches(&NanSensitiveFloatNear);
            }

            TEST_F(FloatNearTest, FloatNearCanDescribeSelf) {
                Matcher<float> m1 = FloatNear(2.0f, 0.5f);
                EXPECT_EQ("is approximately 2 (absolute error <= 0.5)", Describe(m1));
                EXPECT_EQ(
                        "isn't approximately 2 (absolute error > 0.5)", DescribeNegation(m1));

                Matcher<float> m2 = FloatNear(0.5f, 0.5f);
                EXPECT_EQ("is approximately 0.5 (absolute error <= 0.5)", Describe(m2));
                EXPECT_EQ(
                        "isn't approximately 0.5 (absolute error > 0.5)", DescribeNegation(m2));

                Matcher<float> m3 = FloatNear(nan1_, 0.0);
                EXPECT_EQ("never matches", Describe(m3));
                EXPECT_EQ("is anything", DescribeNegation(m3));
            }

            TEST_F(FloatNearTest, NanSensitiveFloatNearCanDescribeSelf) {
                Matcher<float> m1 = NanSensitiveFloatNear(2.0f, 0.5f);
                EXPECT_EQ("is approximately 2 (absolute error <= 0.5)", Describe(m1));
                EXPECT_EQ(
                        "isn't approximately 2 (absolute error > 0.5)", DescribeNegation(m1));

                Matcher<float> m2 = NanSensitiveFloatNear(0.5f, 0.5f);
                EXPECT_EQ("is approximately 0.5 (absolute error <= 0.5)", Describe(m2));
                EXPECT_EQ(
                        "isn't approximately 0.5 (absolute error > 0.5)", DescribeNegation(m2));

                Matcher<float> m3 = NanSensitiveFloatNear(nan1_, 0.1f);
                EXPECT_EQ("is NaN", Describe(m3));
                EXPECT_EQ("isn't NaN", DescribeNegation(m3));
            }

            TEST_F(FloatNearTest, FloatNearCannotMatchNaN) {
                // FloatNear never matches NaN.
                Matcher<float> m = FloatNear(ParentType::nan1_, 0.1f);
                EXPECT_FALSE(m.Matches(nan1_));
                EXPECT_FALSE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST_F(FloatNearTest, NanSensitiveFloatNearCanMatchNaN) {
                // NanSensitiveFloatNear will match NaN.
                Matcher<float> m = NanSensitiveFloatNear(nan1_, 0.1f);
                EXPECT_TRUE(m.Matches(nan1_));
                EXPECT_TRUE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

// Instantiate FloatingPointTest for testing doubles.
            typedef FloatingPointTest<double> DoubleTest;

            TEST_F(DoubleTest, DoubleEqApproximatelyMatchesDoubles) {
                TestMatches(&DoubleEq);
            }

            TEST_F(DoubleTest, NanSensitiveDoubleEqApproximatelyMatchesDoubles) {
                TestMatches(&NanSensitiveDoubleEq);
            }

            TEST_F(DoubleTest, DoubleEqCannotMatchNaN) {
                // DoubleEq never matches NaN.
                Matcher<double> m = DoubleEq(nan1_);
                EXPECT_FALSE(m.Matches(nan1_));
                EXPECT_FALSE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST_F(DoubleTest, NanSensitiveDoubleEqCanMatchNaN) {
                // NanSensitiveDoubleEq will match NaN.
                Matcher<double> m = NanSensitiveDoubleEq(nan1_);
                EXPECT_TRUE(m.Matches(nan1_));
                EXPECT_TRUE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST_F(DoubleTest, DoubleEqCanDescribeSelf) {
                Matcher<double> m1 = DoubleEq(2.0);
                EXPECT_EQ("is approximately 2", Describe(m1));
                EXPECT_EQ("isn't approximately 2", DescribeNegation(m1));

                Matcher<double> m2 = DoubleEq(0.5);
                EXPECT_EQ("is approximately 0.5", Describe(m2));
                EXPECT_EQ("isn't approximately 0.5", DescribeNegation(m2));

                Matcher<double> m3 = DoubleEq(nan1_);
                EXPECT_EQ("never matches", Describe(m3));
                EXPECT_EQ("is anything", DescribeNegation(m3));
            }

            TEST_F(DoubleTest, NanSensitiveDoubleEqCanDescribeSelf) {
                Matcher<double> m1 = NanSensitiveDoubleEq(2.0);
                EXPECT_EQ("is approximately 2", Describe(m1));
                EXPECT_EQ("isn't approximately 2", DescribeNegation(m1));

                Matcher<double> m2 = NanSensitiveDoubleEq(0.5);
                EXPECT_EQ("is approximately 0.5", Describe(m2));
                EXPECT_EQ("isn't approximately 0.5", DescribeNegation(m2));

                Matcher<double> m3 = NanSensitiveDoubleEq(nan1_);
                EXPECT_EQ("is NaN", Describe(m3));
                EXPECT_EQ("isn't NaN", DescribeNegation(m3));
            }

// Instantiate FloatingPointTest for testing floats with a user-specified
// max absolute error.
            typedef FloatingPointNearTest<double> DoubleNearTest;

            TEST_F(DoubleNearTest, DoubleNearMatches) {
                TestNearMatches(&DoubleNear);
            }

            TEST_F(DoubleNearTest, NanSensitiveDoubleNearApproximatelyMatchesDoubles) {
                TestNearMatches(&NanSensitiveDoubleNear);
            }

            TEST_F(DoubleNearTest, DoubleNearCanDescribeSelf) {
                Matcher<double> m1 = DoubleNear(2.0, 0.5);
                EXPECT_EQ("is approximately 2 (absolute error <= 0.5)", Describe(m1));
                EXPECT_EQ(
                        "isn't approximately 2 (absolute error > 0.5)", DescribeNegation(m1));

                Matcher<double> m2 = DoubleNear(0.5, 0.5);
                EXPECT_EQ("is approximately 0.5 (absolute error <= 0.5)", Describe(m2));
                EXPECT_EQ(
                        "isn't approximately 0.5 (absolute error > 0.5)", DescribeNegation(m2));

                Matcher<double> m3 = DoubleNear(nan1_, 0.0);
                EXPECT_EQ("never matches", Describe(m3));
                EXPECT_EQ("is anything", DescribeNegation(m3));
            }

            TEST_F(DoubleNearTest, ExplainsResultWhenMatchFails) {
                EXPECT_EQ("", Explain(DoubleNear(2.0, 0.1), 2.05));
                EXPECT_EQ("which is 0.2 from 2", Explain(DoubleNear(2.0, 0.1), 2.2));
                EXPECT_EQ("which is -0.3 from 2", Explain(DoubleNear(2.0, 0.1), 1.7));

                const std::string explanation =
                        Explain(DoubleNear(2.1, 1e-10), 2.1 + 1.2e-10);
                // Different C++ implementations may print floating-point numbers
                // slightly differently.
                EXPECT_TRUE(explanation == "which is 1.2e-10 from 2.1" ||  // GCC
                            explanation == "which is 1.2e-010 from 2.1")   // MSVC
                                                                                   << " where explanation is \""
                                                                                   << explanation << "\".";
            }

            TEST_F(DoubleNearTest, NanSensitiveDoubleNearCanDescribeSelf) {
                Matcher<double> m1 = NanSensitiveDoubleNear(2.0, 0.5);
                EXPECT_EQ("is approximately 2 (absolute error <= 0.5)", Describe(m1));
                EXPECT_EQ(
                        "isn't approximately 2 (absolute error > 0.5)", DescribeNegation(m1));

                Matcher<double> m2 = NanSensitiveDoubleNear(0.5, 0.5);
                EXPECT_EQ("is approximately 0.5 (absolute error <= 0.5)", Describe(m2));
                EXPECT_EQ(
                        "isn't approximately 0.5 (absolute error > 0.5)", DescribeNegation(m2));

                Matcher<double> m3 = NanSensitiveDoubleNear(nan1_, 0.1);
                EXPECT_EQ("is NaN", Describe(m3));
                EXPECT_EQ("isn't NaN", DescribeNegation(m3));
            }

            TEST_F(DoubleNearTest, DoubleNearCannotMatchNaN) {
                // DoubleNear never matches NaN.
                Matcher<double> m = DoubleNear(ParentType::nan1_, 0.1);
                EXPECT_FALSE(m.Matches(nan1_));
                EXPECT_FALSE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST_F(DoubleNearTest, NanSensitiveDoubleNearCanMatchNaN) {
                // NanSensitiveDoubleNear will match NaN.
                Matcher<double> m = NanSensitiveDoubleNear(nan1_, 0.1);
                EXPECT_TRUE(m.Matches(nan1_));
                EXPECT_TRUE(m.Matches(nan2_));
                EXPECT_FALSE(m.Matches(1.0));
            }

            TEST(PointeeTest, RawPointer) {
                const Matcher<int *> m = Pointee(Ge(0));

                int n = 1;
                EXPECT_TRUE(m.Matches(&n));
                n = -1;
                EXPECT_FALSE(m.Matches(&n));
                EXPECT_FALSE(m.Matches(nullptr));
            }

            TEST(PointeeTest, RawPointerToConst) {
                const Matcher<const double *> m = Pointee(Ge(0));

                double x = 1;
                EXPECT_TRUE(m.Matches(&x));
                x = -1;
                EXPECT_FALSE(m.Matches(&x));
                EXPECT_FALSE(m.Matches(nullptr));
            }

            TEST(PointeeTest, ReferenceToConstRawPointer) {
                const Matcher<int *const &> m = Pointee(Ge(0));

                int n = 1;
                EXPECT_TRUE(m.Matches(&n));
                n = -1;
                EXPECT_FALSE(m.Matches(&n));
                EXPECT_FALSE(m.Matches(nullptr));
            }

            TEST(PointeeTest, ReferenceToNonConstRawPointer) {
                const Matcher<double *&> m = Pointee(Ge(0));

                double x = 1.0;
                double *p = &x;
                EXPECT_TRUE(m.Matches(p));
                x = -1;
                EXPECT_FALSE(m.Matches(p));
                p = nullptr;
                EXPECT_FALSE(m.Matches(p));
            }

            MATCHER_P(FieldIIs, inner_matcher, "") {
                return ExplainMatchResult(inner_matcher, arg.i, result_listener);
            }

#if GTEST_HAS_RTTI
                                                                                                                                    TEST(WhenDynamicCastToTest, SameType) {
  Derived derived;
  derived.i = 4;

  // Right type. A pointer is passed down.
  Base* as_base_ptr = &derived;
  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(Not(IsNull())));
  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(Pointee(FieldIIs(4))));
  EXPECT_THAT(as_base_ptr,
              Not(WhenDynamicCastTo<Derived*>(Pointee(FieldIIs(5)))));
}

TEST(WhenDynamicCastToTest, WrongTypes) {
  Base base;
  Derived derived;
  OtherDerived other_derived;

  // Wrong types. NULL is passed.
  EXPECT_THAT(&base, Not(WhenDynamicCastTo<Derived*>(Pointee(_))));
  EXPECT_THAT(&base, WhenDynamicCastTo<Derived*>(IsNull()));
  Base* as_base_ptr = &derived;
  EXPECT_THAT(as_base_ptr, Not(WhenDynamicCastTo<OtherDerived*>(Pointee(_))));
  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<OtherDerived*>(IsNull()));
  as_base_ptr = &other_derived;
  EXPECT_THAT(as_base_ptr, Not(WhenDynamicCastTo<Derived*>(Pointee(_))));
  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(IsNull()));
}

TEST(WhenDynamicCastToTest, AlreadyNull) {
  // Already NULL.
  Base* as_base_ptr = nullptr;
  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(IsNull()));
}

struct AmbiguousCastTypes {
  class VirtualDerived : public virtual Base {};
  class DerivedSub1 : public VirtualDerived {};
  class DerivedSub2 : public VirtualDerived {};
  class ManyDerivedInHierarchy : public DerivedSub1, public DerivedSub2 {};
};

TEST(WhenDynamicCastToTest, AmbiguousCast) {
  AmbiguousCastTypes::DerivedSub1 sub1;
  AmbiguousCastTypes::ManyDerivedInHierarchy many_derived;
  // Multiply derived from Base. dynamic_cast<> returns NULL.
  Base* as_base_ptr =
      static_cast<AmbiguousCastTypes::DerivedSub1*>(&many_derived);
  EXPECT_THAT(as_base_ptr,
              WhenDynamicCastTo<AmbiguousCastTypes::VirtualDerived*>(IsNull()));
  as_base_ptr = &sub1;
  EXPECT_THAT(
      as_base_ptr,
      WhenDynamicCastTo<AmbiguousCastTypes::VirtualDerived*>(Not(IsNull())));
}

TEST(WhenDynamicCastToTest, Describe) {
  Matcher<Base*> matcher = WhenDynamicCastTo<Derived*>(Pointee(_));
  const std::string prefix =
      "when dynamic_cast to " + internal::GetTypeName<Derived*>() + ", ";
  EXPECT_EQ(prefix + "points to a value that is anything", Describe(matcher));
  EXPECT_EQ(prefix + "does not point to a value that is anything",
            DescribeNegation(matcher));
}

TEST(WhenDynamicCastToTest, Explain) {
  Matcher<Base*> matcher = WhenDynamicCastTo<Derived*>(Pointee(_));
  Base* null = nullptr;
  EXPECT_THAT(Explain(matcher, null), HasSubstr("NULL"));
  Derived derived;
  EXPECT_TRUE(matcher.Matches(&derived));
  EXPECT_THAT(Explain(matcher, &derived), HasSubstr("which points to "));

  // With references, the matcher itself can fail. Test for that one.
  Matcher<const Base&> ref_matcher = WhenDynamicCastTo<const OtherDerived&>(_);
  EXPECT_THAT(Explain(ref_matcher, derived),
              HasSubstr("which cannot be dynamic_cast"));
}

TEST(WhenDynamicCastToTest, GoodReference) {
  Derived derived;
  derived.i = 4;
  Base& as_base_ref = derived;
  EXPECT_THAT(as_base_ref, WhenDynamicCastTo<const Derived&>(FieldIIs(4)));
  EXPECT_THAT(as_base_ref, WhenDynamicCastTo<const Derived&>(Not(FieldIIs(5))));
}

TEST(WhenDynamicCastToTest, BadReference) {
  Derived derived;
  Base& as_base_ref = derived;
  EXPECT_THAT(as_base_ref, Not(WhenDynamicCastTo<const OtherDerived&>(_)));
}
#endif  // GTEST_HAS_RTTI

// Minimal const-propagating pointer.
            template<typename T>
            class ConstPropagatingPtr {
            public:
                typedef T element_type;

                ConstPropagatingPtr() : val_() {}

                explicit ConstPropagatingPtr(T *t) : val_(t) {}

                ConstPropagatingPtr(const ConstPropagatingPtr &other) : val_(other.val_) {}

                T *get() { return val_; }

                T &operator*() { return *val_; }

                // Most smart pointers return non-const T* and T& from the next methods.
                const T *get() const { return val_; }

                const T &operator*() const { return *val_; }

            private:
                T *val_;
            };

            TEST(PointeeTest, WorksWithConstPropagatingPointers) {
                const Matcher<ConstPropagatingPtr<int> > m = Pointee(Lt(5));
                int three = 3;
                const ConstPropagatingPtr<int> co(&three);
                ConstPropagatingPtr<int> o(&three);
                EXPECT_TRUE(m.Matches(o));
                EXPECT_TRUE(m.Matches(co));
                *o = 6;
                EXPECT_FALSE(m.Matches(o));
                EXPECT_FALSE(m.Matches(ConstPropagatingPtr<int>()));
            }

            TEST(PointeeTest, NeverMatchesNull) {
                const Matcher<const char *> m = Pointee(_);
                EXPECT_FALSE(m.Matches(nullptr));
            }

// Tests that we can write Pointee(value) instead of Pointee(Eq(value)).
            TEST(PointeeTest, MatchesAgainstAValue) {
                const Matcher<int *> m = Pointee(5);

                int n = 5;
                EXPECT_TRUE(m.Matches(&n));
                n = -1;
                EXPECT_FALSE(m.Matches(&n));
                EXPECT_FALSE(m.Matches(nullptr));
            }

            TEST(PointeeTest, CanDescribeSelf) {
                const Matcher<int *> m = Pointee(Gt(3));
                EXPECT_EQ("points to a value that is > 3", Describe(m));
                EXPECT_EQ("does not point to a value that is > 3",
                          DescribeNegation(m));
            }

            TEST(PointeeTest, CanExplainMatchResult) {
                const Matcher<const std::string *> m = Pointee(StartsWith("Hi"));

                EXPECT_EQ("", Explain(m, static_cast<const std::string *>(nullptr)));

                const Matcher<long *> m2 = Pointee(GreaterThan(1));  // NOLINT
                long n = 3;  // NOLINT
                EXPECT_EQ("which points to 3" + OfType("long") + ", which is 2 more than 1",
                          Explain(m2, &n));
            }

            TEST(PointeeTest, AlwaysExplainsPointee) {
                const Matcher<int *> m = Pointee(0);
                int n = 42;
                EXPECT_EQ("which points to 42" + OfType("int"), Explain(m, &n));
            }

// An uncopyable class.
            class Uncopyable {
            public:
                Uncopyable() : value_(-1) {}

                explicit Uncopyable(int a_value) : value_(a_value) {}

                int value() const { return value_; }

                void set_value(int i) { value_ = i; }

            private:
                int value_;
                GTEST_DISALLOW_COPY_AND_ASSIGN_(Uncopyable);
            };

// Returns true if and only if x.value() is positive.
            bool ValueIsPositive(const Uncopyable &x) { return x.value() > 0; }

            MATCHER_P(UncopyableIs, inner_matcher, "") {
                return ExplainMatchResult(inner_matcher, arg.value(), result_listener);
            }

// A user-defined struct for testing Field().
            struct AStruct {
                AStruct() : x(0), y(1.0), z(5), p(nullptr) {}

                AStruct(const AStruct &rhs)
                        : x(rhs.x), y(rhs.y), z(rhs.z.value()), p(rhs.p) {}

                int x;           // A non-const field.
                const double y;  // A const field.
                Uncopyable z;    // An uncopyable field.
                const char *p;   // A pointer field.

            private:
                GTEST_DISALLOW_ASSIGN_(AStruct);
            };

// A derived struct for testing Field().
            struct DerivedStruct : public AStruct {
                char ch;

            private:
                GTEST_DISALLOW_ASSIGN_(DerivedStruct);
            };

// Tests that Field(&Foo::field, ...) works when field is non-const.
            TEST(FieldTest, WorksForNonConstField) {
                Matcher<AStruct> m = Field(&AStruct::x, Ge(0));
                Matcher<AStruct> m_with_name = Field("x", &AStruct::x, Ge(0));

                AStruct a;
                EXPECT_TRUE(m.Matches(a));
                EXPECT_TRUE(m_with_name.Matches(a));
                a.x = -1;
                EXPECT_FALSE(m.Matches(a));
                EXPECT_FALSE(m_with_name.Matches(a));
            }

// Tests that Field(&Foo::field, ...) works when field is const.
            TEST(FieldTest, WorksForConstField) {
                AStruct a;

                Matcher<AStruct> m = Field(&AStruct::y, Ge(0.0));
                Matcher<AStruct> m_with_name = Field("y", &AStruct::y, Ge(0.0));
                EXPECT_TRUE(m.Matches(a));
                EXPECT_TRUE(m_with_name.Matches(a));
                m = Field(&AStruct::y, Le(0.0));
                m_with_name = Field("y", &AStruct::y, Le(0.0));
                EXPECT_FALSE(m.Matches(a));
                EXPECT_FALSE(m_with_name.Matches(a));
            }

// Tests that Field(&Foo::field, ...) works when field is not copyable.
            TEST(FieldTest, WorksForUncopyableField) {
                AStruct a;

                Matcher<AStruct> m = Field(&AStruct::z, Truly(ValueIsPositive));
                EXPECT_TRUE(m.Matches(a));
                m = Field(&AStruct::z, Not(Truly(ValueIsPositive)));
                EXPECT_FALSE(m.Matches(a));
            }

// Tests that Field(&Foo::field, ...) works when field is a pointer.
            TEST(FieldTest, WorksForPointerField) {
                // Matching against NULL.
                Matcher<AStruct> m = Field(&AStruct::p, static_cast<const char *>(nullptr));
                AStruct a;
                EXPECT_TRUE(m.Matches(a));
                a.p = "hi";
                EXPECT_FALSE(m.Matches(a));

                // Matching a pointer that is not NULL.
                m = Field(&AStruct::p, StartsWith("hi"));
                a.p = "hill";
                EXPECT_TRUE(m.Matches(a));
                a.p = "hole";
                EXPECT_FALSE(m.Matches(a));
            }

// Tests that Field() works when the object is passed by reference.
            TEST(FieldTest, WorksForByRefArgument) {
                Matcher<const AStruct &> m = Field(&AStruct::x, Ge(0));

                AStruct a;
                EXPECT_TRUE(m.Matches(a));
                a.x = -1;
                EXPECT_FALSE(m.Matches(a));
            }

// Tests that Field(&Foo::field, ...) works when the argument's type
// is a sub-type of Foo.
            TEST(FieldTest, WorksForArgumentOfSubType) {
                // Note that the matcher expects DerivedStruct but we say AStruct
                // inside Field().
                Matcher<const DerivedStruct &> m = Field(&AStruct::x, Ge(0));

                DerivedStruct d;
                EXPECT_TRUE(m.Matches(d));
                d.x = -1;
                EXPECT_FALSE(m.Matches(d));
            }

// Tests that Field(&Foo::field, m) works when field's type and m's
// argument type are compatible but not the same.
            TEST(FieldTest, WorksForCompatibleMatcherType) {
                // The field is an int, but the inner matcher expects a signed char.
                Matcher<const AStruct &> m = Field(&AStruct::x,
                                                   Matcher<signed char>(Ge(0)));

                AStruct a;
                EXPECT_TRUE(m.Matches(a));
                a.x = -1;
                EXPECT_FALSE(m.Matches(a));
            }

// Tests that Field() can describe itself.
            TEST(FieldTest, CanDescribeSelf) {
                Matcher<const AStruct &> m = Field(&AStruct::x, Ge(0));

                EXPECT_EQ("is an object whose given field is >= 0", Describe(m));
                EXPECT_EQ("is an object whose given field isn't >= 0", DescribeNegation(m));
            }

            TEST(FieldTest, CanDescribeSelfWithFieldName) {
                Matcher<const AStruct &> m = Field("field_name", &AStruct::x, Ge(0));

                EXPECT_EQ("is an object whose field `field_name` is >= 0", Describe(m));
                EXPECT_EQ("is an object whose field `field_name` isn't >= 0",
                          DescribeNegation(m));
            }

// Tests that Field() can explain the match result.
            TEST(FieldTest, CanExplainMatchResult) {
                Matcher<const AStruct &> m = Field(&AStruct::x, Ge(0));

                AStruct a;
                a.x = 1;
                EXPECT_EQ("whose given field is 1" + OfType("int"), Explain(m, a));

                m = Field(&AStruct::x, GreaterThan(0));
                EXPECT_EQ(
                        "whose given field is 1" + OfType("int") + ", which is 1 more than 0",
                        Explain(m, a));
            }

            TEST(FieldTest, CanExplainMatchResultWithFieldName) {
                Matcher<const AStruct &> m = Field("field_name", &AStruct::x, Ge(0));

                AStruct a;
                a.x = 1;
                EXPECT_EQ("whose field `field_name` is 1" + OfType("int"), Explain(m, a));

                m = Field("field_name", &AStruct::x, GreaterThan(0));
                EXPECT_EQ("whose field `field_name` is 1" + OfType("int") +
                          ", which is 1 more than 0",
                          Explain(m, a));
            }

// Tests that Field() works when the argument is a pointer to const.
            TEST(FieldForPointerTest, WorksForPointerToConst) {
                Matcher<const AStruct *> m = Field(&AStruct::x, Ge(0));

                AStruct a;
                EXPECT_TRUE(m.Matches(&a));
                a.x = -1;
                EXPECT_FALSE(m.Matches(&a));
            }

// Tests that Field() works when the argument is a pointer to non-const.
            TEST(FieldForPointerTest, WorksForPointerToNonConst) {
                Matcher<AStruct *> m = Field(&AStruct::x, Ge(0));

                AStruct a;
                EXPECT_TRUE(m.Matches(&a));
                a.x = -1;
                EXPECT_FALSE(m.Matches(&a));
            }

// Tests that Field() works when the argument is a reference to a const pointer.
            TEST(FieldForPointerTest, WorksForReferenceToConstPointer) {
                Matcher<AStruct *const &> m = Field(&AStruct::x, Ge(0));

                AStruct a;
                EXPECT_TRUE(m.Matches(&a));
                a.x = -1;
                EXPECT_FALSE(m.Matches(&a));
            }

// Tests that Field() does not match the NULL pointer.
            TEST(FieldForPointerTest, DoesNotMatchNull) {
                Matcher<const AStruct *> m = Field(&AStruct::x, _);
                EXPECT_FALSE(m.Matches(nullptr));
            }

// Tests that Field(&Foo::field, ...) works when the argument's type
// is a sub-type of const Foo*.
            TEST(FieldForPointerTest, WorksForArgumentOfSubType) {
                // Note that the matcher expects DerivedStruct but we say AStruct
                // inside Field().
                Matcher<DerivedStruct *> m = Field(&AStruct::x, Ge(0));

                DerivedStruct d;
                EXPECT_TRUE(m.Matches(&d));
                d.x = -1;
                EXPECT_FALSE(m.Matches(&d));
            }

// Tests that Field() can describe itself when used to match a pointer.
            TEST(FieldForPointerTest, CanDescribeSelf) {
                Matcher<const AStruct *> m = Field(&AStruct::x, Ge(0));

                EXPECT_EQ("is an object whose given field is >= 0", Describe(m));
                EXPECT_EQ("is an object whose given field isn't >= 0", DescribeNegation(m));
            }

            TEST(FieldForPointerTest, CanDescribeSelfWithFieldName) {
                Matcher<const AStruct *> m = Field("field_name", &AStruct::x, Ge(0));

                EXPECT_EQ("is an object whose field `field_name` is >= 0", Describe(m));
                EXPECT_EQ("is an object whose field `field_name` isn't >= 0",
                          DescribeNegation(m));
            }

// Tests that Field() can explain the result of matching a pointer.
            TEST(FieldForPointerTest, CanExplainMatchResult) {
                Matcher<const AStruct *> m = Field(&AStruct::x, Ge(0));

                AStruct a;
                a.x = 1;
                EXPECT_EQ("", Explain(m, static_cast<const AStruct *>(nullptr)));
                EXPECT_EQ("which points to an object whose given field is 1" + OfType("int"),
                          Explain(m, &a));

                m = Field(&AStruct::x, GreaterThan(0));
                EXPECT_EQ("which points to an object whose given field is 1" + OfType("int") +
                          ", which is 1 more than 0", Explain(m, &a));
            }

            TEST(FieldForPointerTest, CanExplainMatchResultWithFieldName) {
                Matcher<const AStruct *> m = Field("field_name", &AStruct::x, Ge(0));

                AStruct a;
                a.x = 1;
                EXPECT_EQ("", Explain(m, static_cast<const AStruct *>(nullptr)));
                EXPECT_EQ(
                        "which points to an object whose field `field_name` is 1" + OfType("int"),
                        Explain(m, &a));

                m = Field("field_name", &AStruct::x, GreaterThan(0));
                EXPECT_EQ("which points to an object whose field `field_name` is 1" +
                          OfType("int") + ", which is 1 more than 0",
                          Explain(m, &a));
            }

// A user-defined class for testing Property().
            class AClass {
            public:
                AClass() : n_(0) {}

                // A getter that returns a non-reference.
                int n() const { return n_; }

                void set_n(int new_n) { n_ = new_n; }

                // A getter that returns a reference to const.
                const std::string &s() const { return s_; }

                const std::string &s_ref() const &{ return s_; }

                void set_s(const std::string &new_s) { s_ = new_s; }

                // A getter that returns a reference to non-const.
                double &x() const { return x_; }

            private:
                int n_;
                std::string s_;

                static double x_;
            };

            double AClass::x_ = 0.0;

// A derived class for testing Property().
            class DerivedClass : public AClass {
            public:
                int k() const { return k_; }

            private:
                int k_;
            };

// Tests that Property(&Foo::property, ...) works when property()
// returns a non-reference.
            TEST(PropertyTest, WorksForNonReferenceProperty) {
                Matcher<const AClass &> m = Property(&AClass::n, Ge(0));
                Matcher<const AClass &> m_with_name = Property("n", &AClass::n, Ge(0));

                AClass a;
                a.set_n(1);
                EXPECT_TRUE(m.Matches(a));
                EXPECT_TRUE(m_with_name.Matches(a));

                a.set_n(-1);
                EXPECT_FALSE(m.Matches(a));
                EXPECT_FALSE(m_with_name.Matches(a));
            }

// Tests that Property(&Foo::property, ...) works when property()
// returns a reference to const.
            TEST(PropertyTest, WorksForReferenceToConstProperty) {
                Matcher<const AClass &> m = Property(&AClass::s, StartsWith("hi"));
                Matcher<const AClass &> m_with_name =
                        Property("s", &AClass::s, StartsWith("hi"));

                AClass a;
                a.set_s("hill");
                EXPECT_TRUE(m.Matches(a));
                EXPECT_TRUE(m_with_name.Matches(a));

                a.set_s("hole");
                EXPECT_FALSE(m.Matches(a));
                EXPECT_FALSE(m_with_name.Matches(a));
            }

// Tests that Property(&Foo::property, ...) works when property() is
// ref-qualified.
            TEST(PropertyTest, WorksForRefQualifiedProperty) {
                Matcher<const AClass &> m = Property(&AClass::s_ref, StartsWith("hi"));
                Matcher<const AClass &> m_with_name =
                        Property("s", &AClass::s_ref, StartsWith("hi"));

                AClass a;
                a.set_s("hill");
                EXPECT_TRUE(m.Matches(a));
                EXPECT_TRUE(m_with_name.Matches(a));

                a.set_s("hole");
                EXPECT_FALSE(m.Matches(a));
                EXPECT_FALSE(m_with_name.Matches(a));
            }

// Tests that Property(&Foo::property, ...) works when property()
// returns a reference to non-const.
            TEST(PropertyTest, WorksForReferenceToNonConstProperty) {
                double x = 0.0;
                AClass a;

                Matcher<const AClass &> m = Property(&AClass::x, Ref(x));
                EXPECT_FALSE(m.Matches(a));

                m = Property(&AClass::x, Not(Ref(x)));
                EXPECT_TRUE(m.Matches(a));
            }

// Tests that Property(&Foo::property, ...) works when the argument is
// passed by value.
            TEST(PropertyTest, WorksForByValueArgument) {
                Matcher<AClass> m = Property(&AClass::s, StartsWith("hi"));

                AClass a;
                a.set_s("hill");
                EXPECT_TRUE(m.Matches(a));

                a.set_s("hole");
                EXPECT_FALSE(m.Matches(a));
            }

// Tests that Property(&Foo::property, ...) works when the argument's
// type is a sub-type of Foo.
            TEST(PropertyTest, WorksForArgumentOfSubType) {
                // The matcher expects a DerivedClass, but inside the Property() we
                // say AClass.
                Matcher<const DerivedClass &> m = Property(&AClass::n, Ge(0));

                DerivedClass d;
                d.set_n(1);
                EXPECT_TRUE(m.Matches(d));

                d.set_n(-1);
                EXPECT_FALSE(m.Matches(d));
            }

// Tests that Property(&Foo::property, m) works when property()'s type
// and m's argument type are compatible but different.
            TEST(PropertyTest, WorksForCompatibleMatcherType) {
                // n() returns an int but the inner matcher expects a signed char.
                Matcher<const AClass &> m = Property(&AClass::n,
                                                     Matcher<signed char>(Ge(0)));

                Matcher<const AClass &> m_with_name =
                        Property("n", &AClass::n, Matcher<signed char>(Ge(0)));

                AClass a;
                EXPECT_TRUE(m.Matches(a));
                EXPECT_TRUE(m_with_name.Matches(a));
                a.set_n(-1);
                EXPECT_FALSE(m.Matches(a));
                EXPECT_FALSE(m_with_name.Matches(a));
            }

// Tests that Property() can describe itself.
            TEST(PropertyTest, CanDescribeSelf) {
                Matcher<const AClass &> m = Property(&AClass::n, Ge(0));

                EXPECT_EQ("is an object whose given property is >= 0", Describe(m));
                EXPECT_EQ("is an object whose given property isn't >= 0",
                          DescribeNegation(m));
            }

            TEST(PropertyTest, CanDescribeSelfWithPropertyName) {
                Matcher<const AClass &> m = Property("fancy_name", &AClass::n, Ge(0));

                EXPECT_EQ("is an object whose property `fancy_name` is >= 0", Describe(m));
                EXPECT_EQ("is an object whose property `fancy_name` isn't >= 0",
                          DescribeNegation(m));
            }

// Tests that Property() can explain the match result.
            TEST(PropertyTest, CanExplainMatchResult) {
                Matcher<const AClass &> m = Property(&AClass::n, Ge(0));

                AClass a;
                a.set_n(1);
                EXPECT_EQ("whose given property is 1" + OfType("int"), Explain(m, a));

                m = Property(&AClass::n, GreaterThan(0));
                EXPECT_EQ(
                        "whose given property is 1" + OfType("int") + ", which is 1 more than 0",
                        Explain(m, a));
            }

            TEST(PropertyTest, CanExplainMatchResultWithPropertyName) {
                Matcher<const AClass &> m = Property("fancy_name", &AClass::n, Ge(0));

                AClass a;
                a.set_n(1);
                EXPECT_EQ("whose property `fancy_name` is 1" + OfType("int"), Explain(m, a));

                m = Property("fancy_name", &AClass::n, GreaterThan(0));
                EXPECT_EQ("whose property `fancy_name` is 1" + OfType("int") +
                          ", which is 1 more than 0",
                          Explain(m, a));
            }

// Tests that Property() works when the argument is a pointer to const.
            TEST(PropertyForPointerTest, WorksForPointerToConst) {
                Matcher<const AClass *> m = Property(&AClass::n, Ge(0));

                AClass a;
                a.set_n(1);
                EXPECT_TRUE(m.Matches(&a));

                a.set_n(-1);
                EXPECT_FALSE(m.Matches(&a));
            }

// Tests that Property() works when the argument is a pointer to non-const.
            TEST(PropertyForPointerTest, WorksForPointerToNonConst) {
                Matcher<AClass *> m = Property(&AClass::s, StartsWith("hi"));

                AClass a;
                a.set_s("hill");
                EXPECT_TRUE(m.Matches(&a));

                a.set_s("hole");
                EXPECT_FALSE(m.Matches(&a));
            }

// Tests that Property() works when the argument is a reference to a
// const pointer.
            TEST(PropertyForPointerTest, WorksForReferenceToConstPointer) {
                Matcher<AClass *const &> m = Property(&AClass::s, StartsWith("hi"));

                AClass a;
                a.set_s("hill");
                EXPECT_TRUE(m.Matches(&a));

                a.set_s("hole");
                EXPECT_FALSE(m.Matches(&a));
            }

// Tests that Property() does not match the NULL pointer.
            TEST(PropertyForPointerTest, WorksForReferenceToNonConstProperty) {
                Matcher<const AClass *> m = Property(&AClass::x, _);
                EXPECT_FALSE(m.Matches(nullptr));
            }

// Tests that Property(&Foo::property, ...) works when the argument's
// type is a sub-type of const Foo*.
            TEST(PropertyForPointerTest, WorksForArgumentOfSubType) {
                // The matcher expects a DerivedClass, but inside the Property() we
                // say AClass.
                Matcher<const DerivedClass *> m = Property(&AClass::n, Ge(0));

                DerivedClass d;
                d.set_n(1);
                EXPECT_TRUE(m.Matches(&d));

                d.set_n(-1);
                EXPECT_FALSE(m.Matches(&d));
            }

// Tests that Property() can describe itself when used to match a pointer.
            TEST(PropertyForPointerTest, CanDescribeSelf) {
                Matcher<const AClass *> m = Property(&AClass::n, Ge(0));

                EXPECT_EQ("is an object whose given property is >= 0", Describe(m));
                EXPECT_EQ("is an object whose given property isn't >= 0",
                          DescribeNegation(m));
            }

            TEST(PropertyForPointerTest, CanDescribeSelfWithPropertyDescription) {
                Matcher<const AClass *> m = Property("fancy_name", &AClass::n, Ge(0));

                EXPECT_EQ("is an object whose property `fancy_name` is >= 0", Describe(m));
                EXPECT_EQ("is an object whose property `fancy_name` isn't >= 0",
                          DescribeNegation(m));
            }

// Tests that Property() can explain the result of matching a pointer.
            TEST(PropertyForPointerTest, CanExplainMatchResult) {
                Matcher<const AClass *> m = Property(&AClass::n, Ge(0));

                AClass a;
                a.set_n(1);
                EXPECT_EQ("", Explain(m, static_cast<const AClass *>(nullptr)));
                EXPECT_EQ(
                        "which points to an object whose given property is 1" + OfType("int"),
                        Explain(m, &a));

                m = Property(&AClass::n, GreaterThan(0));
                EXPECT_EQ("which points to an object whose given property is 1" +
                          OfType("int") + ", which is 1 more than 0",
                          Explain(m, &a));
            }

            TEST(PropertyForPointerTest, CanExplainMatchResultWithPropertyName) {
                Matcher<const AClass *> m = Property("fancy_name", &AClass::n, Ge(0));

                AClass a;
                a.set_n(1);
                EXPECT_EQ("", Explain(m, static_cast<const AClass *>(nullptr)));
                EXPECT_EQ("which points to an object whose property `fancy_name` is 1" +
                          OfType("int"),
                          Explain(m, &a));

                m = Property("fancy_name", &AClass::n, GreaterThan(0));
                EXPECT_EQ("which points to an object whose property `fancy_name` is 1" +
                          OfType("int") + ", which is 1 more than 0",
                          Explain(m, &a));
            }

// Tests ResultOf.

// Tests that ResultOf(f, ...) compiles and works as expected when f is a
// function pointer.
            std::string IntToStringFunction(int input) {
                return input == 1 ? "foo" : "bar";
            }

            TEST(ResultOfTest, WorksForFunctionPointers) {
                Matcher<int> matcher = ResultOf(&IntToStringFunction, Eq(std::string("foo")));

                EXPECT_TRUE(matcher.Matches(1));
                EXPECT_FALSE(matcher.Matches(2));
            }

// Tests that ResultOf() can describe itself.
            TEST(ResultOfTest, CanDescribeItself) {
                Matcher<int> matcher = ResultOf(&IntToStringFunction, StrEq("foo"));

                EXPECT_EQ("is mapped by the given callable to a value that "
                          "is equal to \"foo\"", Describe(matcher));
                EXPECT_EQ("is mapped by the given callable to a value that "
                          "isn't equal to \"foo\"", DescribeNegation(matcher));
            }

// Tests that ResultOf() can explain the match result.
            int IntFunction(int input) { return input == 42 ? 80 : 90; }

            TEST(ResultOfTest, CanExplainMatchResult) {
                Matcher<int> matcher = ResultOf(&IntFunction, Ge(85));
                EXPECT_EQ("which is mapped by the given callable to 90" + OfType("int"),
                          Explain(matcher, 36));

                matcher = ResultOf(&IntFunction, GreaterThan(85));
                EXPECT_EQ("which is mapped by the given callable to 90" + OfType("int") +
                          ", which is 5 more than 85", Explain(matcher, 36));
            }

// Tests that ResultOf(f, ...) compiles and works as expected when f(x)
// returns a non-reference.
            TEST(ResultOfTest, WorksForNonReferenceResults) {
                Matcher<int> matcher = ResultOf(&IntFunction, Eq(80));

                EXPECT_TRUE(matcher.Matches(42));
                EXPECT_FALSE(matcher.Matches(36));
            }

// Tests that ResultOf(f, ...) compiles and works as expected when f(x)
// returns a reference to non-const.
            double &DoubleFunction(double &input) { return input; }  // NOLINT

            Uncopyable &RefUncopyableFunction(Uncopyable &obj) {  // NOLINT
                return obj;
            }

            TEST(ResultOfTest, WorksForReferenceToNonConstResults) {
                double x = 3.14;
                double x2 = x;
                Matcher<double &> matcher = ResultOf(&DoubleFunction, Ref(x));

                EXPECT_TRUE(matcher.Matches(x));
                EXPECT_FALSE(matcher.Matches(x2));

                // Test that ResultOf works with uncopyable objects
                Uncopyable obj(0);
                Uncopyable obj2(0);
                Matcher<Uncopyable &> matcher2 =
                        ResultOf(&RefUncopyableFunction, Ref(obj));

                EXPECT_TRUE(matcher2.Matches(obj));
                EXPECT_FALSE(matcher2.Matches(obj2));
            }

// Tests that ResultOf(f, ...) compiles and works as expected when f(x)
// returns a reference to const.
            const std::string &StringFunction(const std::string &input) { return input; }

            TEST(ResultOfTest, WorksForReferenceToConstResults) {
                std::string s = "foo";
                std::string s2 = s;
                Matcher<const std::string &> matcher = ResultOf(&StringFunction, Ref(s));

                EXPECT_TRUE(matcher.Matches(s));
                EXPECT_FALSE(matcher.Matches(s2));
            }

// Tests that ResultOf(f, m) works when f(x) and m's
// argument types are compatible but different.
            TEST(ResultOfTest, WorksForCompatibleMatcherTypes) {
                // IntFunction() returns int but the inner matcher expects a signed char.
                Matcher<int> matcher = ResultOf(IntFunction, Matcher<signed char>(Ge(85)));

                EXPECT_TRUE(matcher.Matches(36));
                EXPECT_FALSE(matcher.Matches(42));
            }

// Tests that the program aborts when ResultOf is passed
// a NULL function pointer.
            TEST(ResultOfDeathTest, DiesOnNullFunctionPointers) {
                EXPECT_DEATH_IF_SUPPORTED(
                        ResultOf(static_cast<std::string (*)(int dummy)>(nullptr),
                                 Eq(std::string("foo"))),
                        "NULL function pointer is passed into ResultOf\\(\\)\\.");
            }

// Tests that ResultOf(f, ...) compiles and works as expected when f is a
// function reference.
            TEST(ResultOfTest, WorksForFunctionReferences) {
                Matcher<int> matcher = ResultOf(IntToStringFunction, StrEq("foo"));
                EXPECT_TRUE(matcher.Matches(1));
                EXPECT_FALSE(matcher.Matches(2));
            }

// Tests that ResultOf(f, ...) compiles and works as expected when f is a
// function object.
            struct Functor {
                std::string operator()(int input) const {
                    return IntToStringFunction(input);
                }
            };

            TEST(ResultOfTest, WorksForFunctors) {
                Matcher<int> matcher = ResultOf(Functor(), Eq(std::string("foo")));

                EXPECT_TRUE(matcher.Matches(1));
                EXPECT_FALSE(matcher.Matches(2));
            }

// Tests that ResultOf(f, ...) compiles and works as expected when f is a
// functor with more than one operator() defined. ResultOf() must work
// for each defined operator().
            struct PolymorphicFunctor {
                typedef int result_type;

                int operator()(int n) { return n; }

                int operator()(const char *s) { return static_cast<int>(strlen(s)); }

                std::string operator()(int *p) { return p ? "good ptr" : "null"; }
            };

            TEST(ResultOfTest, WorksForPolymorphicFunctors) {
                Matcher<int> matcher_int = ResultOf(PolymorphicFunctor(), Ge(5));

                EXPECT_TRUE(matcher_int.Matches(10));
                EXPECT_FALSE(matcher_int.Matches(2));

                Matcher<const char *> matcher_string = ResultOf(PolymorphicFunctor(), Ge(5));

                EXPECT_TRUE(matcher_string.Matches("long string"));
                EXPECT_FALSE(matcher_string.Matches("shrt"));
            }

            TEST(ResultOfTest, WorksForPolymorphicFunctorsIgnoringResultType) {
                Matcher<int *> matcher = ResultOf(PolymorphicFunctor(), "good ptr");

                int n = 0;
                EXPECT_TRUE(matcher.Matches(&n));
                EXPECT_FALSE(matcher.Matches(nullptr));
            }

            TEST(ResultOfTest, WorksForLambdas) {
                Matcher<int> matcher = ResultOf(
                        [](int str_len) {
                            return std::string(static_cast<size_t>(str_len), 'x');
                        },
                        "xxx");
                EXPECT_TRUE(matcher.Matches(3));
                EXPECT_FALSE(matcher.Matches(1));
            }

            TEST(ResultOfTest, WorksForNonCopyableArguments) {
                Matcher<std::unique_ptr<int>> matcher = ResultOf(
                        [](const std::unique_ptr<int> &str_len) {
                            return std::string(static_cast<size_t>(*str_len), 'x');
                        },
                        "xxx");
                EXPECT_TRUE(matcher.Matches(std::unique_ptr<int>(new int(3))));
                EXPECT_FALSE(matcher.Matches(std::unique_ptr<int>(new int(1))));
            }

            const int *ReferencingFunction(const int &n) { return &n; }

            struct ReferencingFunctor {
                typedef const int *result_type;

                result_type operator()(const int &n) { return &n; }
            };

            TEST(ResultOfTest, WorksForReferencingCallables) {
                const int n = 1;
                const int n2 = 1;
                Matcher<const int &> matcher2 = ResultOf(ReferencingFunction, Eq(&n));
                EXPECT_TRUE(matcher2.Matches(n));
                EXPECT_FALSE(matcher2.Matches(n2));

                Matcher<const int &> matcher3 = ResultOf(ReferencingFunctor(), Eq(&n));
                EXPECT_TRUE(matcher3.Matches(n));
                EXPECT_FALSE(matcher3.Matches(n2));
            }

            class DivisibleByImpl {
            public:
                explicit DivisibleByImpl(int a_divider) : divider_(a_divider) {}

                // For testing using ExplainMatchResultTo() with polymorphic matchers.
                template<typename T>
                bool MatchAndExplain(const T &n, MatchResultListener *listener) const {
                    *listener << "which is " << (n % divider_) << " modulo "
                              << divider_;
                    return (n % divider_) == 0;
                }

                void DescribeTo(ostream *os) const {
                    *os << "is divisible by " << divider_;
                }

                void DescribeNegationTo(ostream *os) const {
                    *os << "is not divisible by " << divider_;
                }

                void set_divider(int a_divider) { divider_ = a_divider; }

                int divider() const { return divider_; }

            private:
                int divider_;
            };

            PolymorphicMatcher<DivisibleByImpl> DivisibleBy(int n) {
                return MakePolymorphicMatcher(DivisibleByImpl(n));
            }

// Tests that when AllOf() fails, only the first failing matcher is
// asked to explain why.
            TEST(ExplainMatchResultTest, AllOf_False_False) {
                const Matcher<int> m = AllOf(DivisibleBy(4), DivisibleBy(3));
                EXPECT_EQ("which is 1 modulo 4", Explain(m, 5));
            }

// Tests that when AllOf() fails, only the first failing matcher is
// asked to explain why.
            TEST(ExplainMatchResultTest, AllOf_False_True) {
                const Matcher<int> m = AllOf(DivisibleBy(4), DivisibleBy(3));
                EXPECT_EQ("which is 2 modulo 4", Explain(m, 6));
            }

// Tests that when AllOf() fails, only the first failing matcher is
// asked to explain why.
            TEST(ExplainMatchResultTest, AllOf_True_False) {
                const Matcher<int> m = AllOf(Ge(1), DivisibleBy(3));
                EXPECT_EQ("which is 2 modulo 3", Explain(m, 5));
            }

// Tests that when AllOf() succeeds, all matchers are asked to explain
// why.
            TEST(ExplainMatchResultTest, AllOf_True_True) {
                const Matcher<int> m = AllOf(DivisibleBy(2), DivisibleBy(3));
                EXPECT_EQ("which is 0 modulo 2, and which is 0 modulo 3", Explain(m, 6));
            }

            TEST(ExplainMatchResultTest, AllOf_True_True_2) {
                const Matcher<int> m = AllOf(Ge(2), Le(3));
                EXPECT_EQ("", Explain(m, 2));
            }

            TEST(ExplainmatcherResultTest, MonomorphicMatcher) {
                const Matcher<int> m = GreaterThan(5);
                EXPECT_EQ("which is 1 more than 5", Explain(m, 6));
            }

// The following two tests verify that values without a public copy
// ctor can be used as arguments to matchers like Eq(), Ge(), and etc
// with the help of ByRef().

            class NotCopyable {
            public:
                explicit NotCopyable(int a_value) : value_(a_value) {}

                int value() const { return value_; }

                bool operator==(const NotCopyable &rhs) const {
                    return value() == rhs.value();
                }

                bool operator>=(const NotCopyable &rhs) const {
                    return value() >= rhs.value();
                }

            private:
                int value_;

                GTEST_DISALLOW_COPY_AND_ASSIGN_(NotCopyable);
            };

            TEST(ByRefTest, AllowsNotCopyableConstValueInMatchers) {
                const NotCopyable const_value1(1);
                const Matcher<const NotCopyable &> m = Eq(ByRef(const_value1));

                const NotCopyable n1(1), n2(2);
                EXPECT_TRUE(m.Matches(n1));
                EXPECT_FALSE(m.Matches(n2));
            }

            TEST(ByRefTest, AllowsNotCopyableValueInMatchers) {
                NotCopyable value2(2);
                const Matcher<NotCopyable &> m = Ge(ByRef(value2));

                NotCopyable n1(1), n2(2);
                EXPECT_FALSE(m.Matches(n1));
                EXPECT_TRUE(m.Matches(n2));
            }

            TEST(IsEmptyTest, ImplementsIsEmpty) {
                vector<int> container;
                EXPECT_THAT(container, IsEmpty());
                container.push_back(0);
                EXPECT_THAT(container, Not(IsEmpty()));
                container.push_back(1);
                EXPECT_THAT(container, Not(IsEmpty()));
            }

            TEST(IsEmptyTest, WorksWithString) {
                std::string text;
                EXPECT_THAT(text, IsEmpty());
                text = "foo";
                EXPECT_THAT(text, Not(IsEmpty()));
                text = std::string("\0", 1);
                EXPECT_THAT(text, Not(IsEmpty()));
            }

            TEST(IsEmptyTest, CanDescribeSelf) {
                Matcher<vector<int> > m = IsEmpty();
                EXPECT_EQ("is empty", Describe(m));
                EXPECT_EQ("isn't empty", DescribeNegation(m));
            }

            TEST(IsEmptyTest, ExplainsResult) {
                Matcher<vector<int> > m = IsEmpty();
                vector<int> container;
                EXPECT_EQ("", Explain(m, container));
                container.push_back(0);
                EXPECT_EQ("whose size is 1", Explain(m, container));
            }

            TEST(IsEmptyTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(IsEmpty()));
                helper.Call({});
            }

            TEST(IsTrueTest, IsTrueIsFalse) {
                EXPECT_THAT(true, IsTrue());
                EXPECT_THAT(false, IsFalse());
                EXPECT_THAT(true, Not(IsFalse()));
                EXPECT_THAT(false, Not(IsTrue()));
                EXPECT_THAT(0, Not(IsTrue()));
                EXPECT_THAT(0, IsFalse());
                EXPECT_THAT(nullptr, Not(IsTrue()));
                EXPECT_THAT(nullptr, IsFalse());
                EXPECT_THAT(-1, IsTrue());
                EXPECT_THAT(-1, Not(IsFalse()));
                EXPECT_THAT(1, IsTrue());
                EXPECT_THAT(1, Not(IsFalse()));
                EXPECT_THAT(2, IsTrue());
                EXPECT_THAT(2, Not(IsFalse()));
                int a = 42;
                EXPECT_THAT(a, IsTrue());
                EXPECT_THAT(a, Not(IsFalse()));
                EXPECT_THAT(&a, IsTrue());
                EXPECT_THAT(&a, Not(IsFalse()));
                EXPECT_THAT(false, Not(IsTrue()));
                EXPECT_THAT(true, Not(IsFalse()));
                EXPECT_THAT(std::true_type(), IsTrue());
                EXPECT_THAT(std::true_type(), Not(IsFalse()));
                EXPECT_THAT(std::false_type(), IsFalse());
                EXPECT_THAT(std::false_type(), Not(IsTrue()));
                EXPECT_THAT(nullptr, Not(IsTrue()));
                EXPECT_THAT(nullptr, IsFalse());
                std::unique_ptr<int> null_unique;
                std::unique_ptr<int> nonnull_unique(new int(0));
                EXPECT_THAT(null_unique, Not(IsTrue()));
                EXPECT_THAT(null_unique, IsFalse());
                EXPECT_THAT(nonnull_unique, IsTrue());
                EXPECT_THAT(nonnull_unique, Not(IsFalse()));
            }

            TEST(SizeIsTest, ImplementsSizeIs) {
                vector<int> container;
                EXPECT_THAT(container, SizeIs(0));
                EXPECT_THAT(container, Not(SizeIs(1)));
                container.push_back(0);
                EXPECT_THAT(container, Not(SizeIs(0)));
                EXPECT_THAT(container, SizeIs(1));
                container.push_back(0);
                EXPECT_THAT(container, Not(SizeIs(0)));
                EXPECT_THAT(container, SizeIs(2));
            }

            TEST(SizeIsTest, WorksWithMap) {
                map<std::string, int> container;
                EXPECT_THAT(container, SizeIs(0));
                EXPECT_THAT(container, Not(SizeIs(1)));
                container.insert(make_pair("foo", 1));
                EXPECT_THAT(container, Not(SizeIs(0)));
                EXPECT_THAT(container, SizeIs(1));
                container.insert(make_pair("bar", 2));
                EXPECT_THAT(container, Not(SizeIs(0)));
                EXPECT_THAT(container, SizeIs(2));
            }

            TEST(SizeIsTest, WorksWithReferences) {
                vector<int> container;
                Matcher<const vector<int> &> m = SizeIs(1);
                EXPECT_THAT(container, Not(m));
                container.push_back(0);
                EXPECT_THAT(container, m);
            }

            TEST(SizeIsTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(SizeIs(3)));
                helper.Call(MakeUniquePtrs({1, 2, 3}));
            }

// SizeIs should work for any type that provides a size() member function.
// For example, a size_type member type should not need to be provided.
            struct MinimalistCustomType {
                int size() const { return 1; }
            };

            TEST(SizeIsTest, WorksWithMinimalistCustomType) {
                MinimalistCustomType container;
                EXPECT_THAT(container, SizeIs(1));
                EXPECT_THAT(container, Not(SizeIs(0)));
            }

            TEST(SizeIsTest, CanDescribeSelf) {
                Matcher<vector<int> > m = SizeIs(2);
                EXPECT_EQ("size is equal to 2", Describe(m));
                EXPECT_EQ("size isn't equal to 2", DescribeNegation(m));
            }

            TEST(SizeIsTest, ExplainsResult) {
                Matcher<vector<int> > m1 = SizeIs(2);
                Matcher<vector<int> > m2 = SizeIs(Lt(2u));
                Matcher<vector<int> > m3 = SizeIs(AnyOf(0, 3));
                Matcher<vector<int> > m4 = SizeIs(GreaterThan(1));
                vector<int> container;
                EXPECT_EQ("whose size 0 doesn't match", Explain(m1, container));
                EXPECT_EQ("whose size 0 matches", Explain(m2, container));
                EXPECT_EQ("whose size 0 matches", Explain(m3, container));
                EXPECT_EQ("whose size 0 doesn't match, which is 1 less than 1",
                          Explain(m4, container));
                container.push_back(0);
                container.push_back(0);
                EXPECT_EQ("whose size 2 matches", Explain(m1, container));
                EXPECT_EQ("whose size 2 doesn't match", Explain(m2, container));
                EXPECT_EQ("whose size 2 doesn't match", Explain(m3, container));
                EXPECT_EQ("whose size 2 matches, which is 1 more than 1",
                          Explain(m4, container));
            }

#if GTEST_HAS_TYPED_TEST
// Tests ContainerEq with different container types, and
// different element types.

            template<typename T>
            class ContainerEqTest : public testing::Test {
            };

            typedef testing::Types<
                    set<int>,
                    vector<size_t>,
                    multiset<size_t>,
                    list<int> >
                    ContainerEqTestTypes;

            TYPED_TEST_SUITE(ContainerEqTest, ContainerEqTestTypes);

// Tests that the filled container is equal to itself.
            TYPED_TEST(ContainerEqTest, EqualsSelf) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                TypeParam my_set(vals, vals + 6);
                const Matcher<TypeParam> m = ContainerEq(my_set);
                EXPECT_TRUE(m.Matches(my_set));
                EXPECT_EQ("", Explain(m, my_set));
            }

// Tests that missing values are reported.
            TYPED_TEST(ContainerEqTest, ValueMissing) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {2, 1, 8, 5};
                TypeParam my_set(vals, vals + 6);
                TypeParam test_set(test_vals, test_vals + 4);
                const Matcher<TypeParam> m = ContainerEq(my_set);
                EXPECT_FALSE(m.Matches(test_set));
                EXPECT_EQ("which doesn't have these expected elements: 3",
                          Explain(m, test_set));
            }

// Tests that added values are reported.
            TYPED_TEST(ContainerEqTest, ValueAdded) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {1, 2, 3, 5, 8, 46};
                TypeParam my_set(vals, vals + 6);
                TypeParam test_set(test_vals, test_vals + 6);
                const Matcher<const TypeParam &> m = ContainerEq(my_set);
                EXPECT_FALSE(m.Matches(test_set));
                EXPECT_EQ("which has these unexpected elements: 46", Explain(m, test_set));
            }

// Tests that added and missing values are reported together.
            TYPED_TEST(ContainerEqTest, ValueAddedAndRemoved) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {1, 2, 3, 8, 46};
                TypeParam my_set(vals, vals + 6);
                TypeParam test_set(test_vals, test_vals + 5);
                const Matcher<TypeParam> m = ContainerEq(my_set);
                EXPECT_FALSE(m.Matches(test_set));
                EXPECT_EQ("which has these unexpected elements: 46,\n"
                          "and doesn't have these expected elements: 5",
                          Explain(m, test_set));
            }

// Tests duplicated value -- expect no explanation.
            TYPED_TEST(ContainerEqTest, DuplicateDifference) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {1, 2, 3, 5, 8};
                TypeParam my_set(vals, vals + 6);
                TypeParam test_set(test_vals, test_vals + 5);
                const Matcher<const TypeParam &> m = ContainerEq(my_set);
                // Depending on the container, match may be true or false
                // But in any case there should be no explanation.
                EXPECT_EQ("", Explain(m, test_set));
            }

#endif  // GTEST_HAS_TYPED_TEST

// Tests that multiple missing values are reported.
// Using just vector here, so order is predictable.
            TEST(ContainerEqExtraTest, MultipleValuesMissing) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {2, 1, 5};
                vector<int> my_set(vals, vals + 6);
                vector<int> test_set(test_vals, test_vals + 3);
                const Matcher<vector<int> > m = ContainerEq(my_set);
                EXPECT_FALSE(m.Matches(test_set));
                EXPECT_EQ("which doesn't have these expected elements: 3, 8",
                          Explain(m, test_set));
            }

// Tests that added values are reported.
// Using just vector here, so order is predictable.
            TEST(ContainerEqExtraTest, MultipleValuesAdded) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {1, 2, 92, 3, 5, 8, 46};
                list<size_t> my_set(vals, vals + 6);
                list<size_t> test_set(test_vals, test_vals + 7);
                const Matcher<const list<size_t> &> m = ContainerEq(my_set);
                EXPECT_FALSE(m.Matches(test_set));
                EXPECT_EQ("which has these unexpected elements: 92, 46",
                          Explain(m, test_set));
            }

// Tests that added and missing values are reported together.
            TEST(ContainerEqExtraTest, MultipleValuesAddedAndRemoved) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {1, 2, 3, 92, 46};
                list<size_t> my_set(vals, vals + 6);
                list<size_t> test_set(test_vals, test_vals + 5);
                const Matcher<const list<size_t> > m = ContainerEq(my_set);
                EXPECT_FALSE(m.Matches(test_set));
                EXPECT_EQ("which has these unexpected elements: 92, 46,\n"
                          "and doesn't have these expected elements: 5, 8",
                          Explain(m, test_set));
            }

// Tests to see that duplicate elements are detected,
// but (as above) not reported in the explanation.
            TEST(ContainerEqExtraTest, MultiSetOfIntDuplicateDifference) {
                static const int vals[] = {1, 1, 2, 3, 5, 8};
                static const int test_vals[] = {1, 2, 3, 5, 8};
                vector<int> my_set(vals, vals + 6);
                vector<int> test_set(test_vals, test_vals + 5);
                const Matcher<vector<int> > m = ContainerEq(my_set);
                EXPECT_TRUE(m.Matches(my_set));
                EXPECT_FALSE(m.Matches(test_set));
                // There is nothing to report when both sets contain all the same values.
                EXPECT_EQ("", Explain(m, test_set));
            }

// Tests that ContainerEq works for non-trivial associative containers,
// like maps.
            TEST(ContainerEqExtraTest, WorksForMaps) {
                map<int, std::string> my_map;
                my_map[0] = "a";
                my_map[1] = "b";

                map<int, std::string> test_map;
                test_map[0] = "aa";
                test_map[1] = "b";

                const Matcher<const map<int, std::string> &> m = ContainerEq(my_map);
                EXPECT_TRUE(m.Matches(my_map));
                EXPECT_FALSE(m.Matches(test_map));

                EXPECT_EQ("which has these unexpected elements: (0, \"aa\"),\n"
                          "and doesn't have these expected elements: (0, \"a\")",
                          Explain(m, test_map));
            }

            TEST(ContainerEqExtraTest, WorksForNativeArray) {
                int a1[] = {1, 2, 3};
                int a2[] = {1, 2, 3};
                int b[] = {1, 2, 4};

                EXPECT_THAT(a1, ContainerEq(a2));
                EXPECT_THAT(a1, Not(ContainerEq(b)));
            }

            TEST(ContainerEqExtraTest, WorksForTwoDimensionalNativeArray) {
                const char a1[][3] = {"hi", "lo"};
                const char a2[][3] = {"hi", "lo"};
                const char b[][3] = {"lo", "hi"};

                // Tests using ContainerEq() in the first dimension.
                EXPECT_THAT(a1, ContainerEq(a2));
                EXPECT_THAT(a1, Not(ContainerEq(b)));

                // Tests using ContainerEq() in the second dimension.
                EXPECT_THAT(a1, ElementsAre(ContainerEq(a2[0]), ContainerEq(a2[1])));
                EXPECT_THAT(a1, ElementsAre(Not(ContainerEq(b[0])), ContainerEq(a2[1])));
            }

            TEST(ContainerEqExtraTest, WorksForNativeArrayAsTuple) {
                const int a1[] = {1, 2, 3};
                const int a2[] = {1, 2, 3};
                const int b[] = {1, 2, 3, 4};

                const int *const p1 = a1;
                EXPECT_THAT(std::make_tuple(p1, 3), ContainerEq(a2));
                EXPECT_THAT(std::make_tuple(p1, 3), Not(ContainerEq(b)));

                const int c[] = {1, 3, 2};
                EXPECT_THAT(std::make_tuple(p1, 3), Not(ContainerEq(c)));
            }

            TEST(ContainerEqExtraTest, CopiesNativeArrayParameter) {
                std::string a1[][3] = {
                        {"hi",  "hello",   "ciao"},
                        {"bye", "see you", "ciao"}
                };

                std::string a2[][3] = {
                        {"hi",  "hello",   "ciao"},
                        {"bye", "see you", "ciao"}
                };

                const Matcher<const std::string(&)[2][3]> m = ContainerEq(a2);
                EXPECT_THAT(a1, m);

                a2[0][0] = "ha";
                EXPECT_THAT(a1, m);
            }

            TEST(WhenSortedByTest, WorksForEmptyContainer) {
                const vector<int> numbers;
                EXPECT_THAT(numbers, WhenSortedBy(less<int>(), ElementsAre()));
                EXPECT_THAT(numbers, Not(WhenSortedBy(less<int>(), ElementsAre(1))));
            }

            TEST(WhenSortedByTest, WorksForNonEmptyContainer) {
                vector<unsigned> numbers;
                numbers.push_back(3);
                numbers.push_back(1);
                numbers.push_back(2);
                numbers.push_back(2);
                EXPECT_THAT(numbers, WhenSortedBy(greater<unsigned>(),
                                                  ElementsAre(3, 2, 2, 1)));
                EXPECT_THAT(numbers, Not(WhenSortedBy(greater<unsigned>(),
                                                      ElementsAre(1, 2, 2, 3))));
            }

            TEST(WhenSortedByTest, WorksForNonVectorContainer) {
                list<std::string> words;
                words.push_back("say");
                words.push_back("hello");
                words.push_back("world");
                EXPECT_THAT(words, WhenSortedBy(less<std::string>(),
                                                ElementsAre("hello", "say", "world")));
                EXPECT_THAT(words, Not(WhenSortedBy(less<std::string>(),
                                                    ElementsAre("say", "hello", "world"))));
            }

            TEST(WhenSortedByTest, WorksForNativeArray) {
                const int numbers[] = {1, 3, 2, 4};
                const int sorted_numbers[] = {1, 2, 3, 4};
                EXPECT_THAT(numbers, WhenSortedBy(less<int>(), ElementsAre(1, 2, 3, 4)));
                EXPECT_THAT(numbers, WhenSortedBy(less<int>(),
                                                  ElementsAreArray(sorted_numbers)));
                EXPECT_THAT(numbers, Not(WhenSortedBy(less<int>(), ElementsAre(1, 3, 2, 4))));
            }

            TEST(WhenSortedByTest, CanDescribeSelf) {
                const Matcher<vector<int> > m = WhenSortedBy(less<int>(), ElementsAre(1, 2));
                EXPECT_EQ("(when sorted) has 2 elements where\n"
                          "element #0 is equal to 1,\n"
                          "element #1 is equal to 2",
                          Describe(m));
                EXPECT_EQ("(when sorted) doesn't have 2 elements, or\n"
                          "element #0 isn't equal to 1, or\n"
                          "element #1 isn't equal to 2",
                          DescribeNegation(m));
            }

            TEST(WhenSortedByTest, ExplainsMatchResult) {
                const int a[] = {2, 1};
                EXPECT_EQ("which is { 1, 2 } when sorted, whose element #0 doesn't match",
                          Explain(WhenSortedBy(less<int>(), ElementsAre(2, 3)), a));
                EXPECT_EQ("which is { 1, 2 } when sorted",
                          Explain(WhenSortedBy(less<int>(), ElementsAre(1, 2)), a));
            }

// WhenSorted() is a simple wrapper on WhenSortedBy().  Hence we don't
// need to test it as exhaustively as we test the latter.

            TEST(WhenSortedTest, WorksForEmptyContainer) {
                const vector<int> numbers;
                EXPECT_THAT(numbers, WhenSorted(ElementsAre()));
                EXPECT_THAT(numbers, Not(WhenSorted(ElementsAre(1))));
            }

            TEST(WhenSortedTest, WorksForNonEmptyContainer) {
                list<std::string> words;
                words.push_back("3");
                words.push_back("1");
                words.push_back("2");
                words.push_back("2");
                EXPECT_THAT(words, WhenSorted(ElementsAre("1", "2", "2", "3")));
                EXPECT_THAT(words, Not(WhenSorted(ElementsAre("3", "1", "2", "2"))));
            }

            TEST(WhenSortedTest, WorksForMapTypes) {
                map<std::string, int> word_counts;
                word_counts["and"] = 1;
                word_counts["the"] = 1;
                word_counts["buffalo"] = 2;
                EXPECT_THAT(word_counts,
                            WhenSorted(ElementsAre(Pair("and", 1), Pair("buffalo", 2),
                                                   Pair("the", 1))));
                EXPECT_THAT(word_counts,
                            Not(WhenSorted(ElementsAre(Pair("and", 1), Pair("the", 1),
                                                       Pair("buffalo", 2)))));
            }

            TEST(WhenSortedTest, WorksForMultiMapTypes) {
                multimap<int, int> ifib;
                ifib.insert(make_pair(8, 6));
                ifib.insert(make_pair(2, 3));
                ifib.insert(make_pair(1, 1));
                ifib.insert(make_pair(3, 4));
                ifib.insert(make_pair(1, 2));
                ifib.insert(make_pair(5, 5));
                EXPECT_THAT(ifib, WhenSorted(ElementsAre(Pair(1, 1),
                                                         Pair(1, 2),
                                                         Pair(2, 3),
                                                         Pair(3, 4),
                                                         Pair(5, 5),
                                                         Pair(8, 6))));
                EXPECT_THAT(ifib, Not(WhenSorted(ElementsAre(Pair(8, 6),
                                                             Pair(2, 3),
                                                             Pair(1, 1),
                                                             Pair(3, 4),
                                                             Pair(1, 2),
                                                             Pair(5, 5)))));
            }

            TEST(WhenSortedTest, WorksForPolymorphicMatcher) {
                std::deque<int> d;
                d.push_back(2);
                d.push_back(1);
                EXPECT_THAT(d, WhenSorted(ElementsAre(1, 2)));
                EXPECT_THAT(d, Not(WhenSorted(ElementsAre(2, 1))));
            }

            TEST(WhenSortedTest, WorksForVectorConstRefMatcher) {
                std::deque<int> d;
                d.push_back(2);
                d.push_back(1);
                Matcher<const std::vector<int> &> vector_match = ElementsAre(1, 2);
                EXPECT_THAT(d, WhenSorted(vector_match));
                Matcher<const std::vector<int> &> not_vector_match = ElementsAre(2, 1);
                EXPECT_THAT(d, Not(WhenSorted(not_vector_match)));
            }

// Deliberately bare pseudo-container.
// Offers only begin() and end() accessors, yielding InputIterator.
            template<typename T>
            class Streamlike {
            private:
                class ConstIter;

            public:
                typedef ConstIter const_iterator;
                typedef T value_type;

                template<typename InIter>
                Streamlike(InIter first, InIter last) : remainder_(first, last) {}

                const_iterator begin() const {
                    return const_iterator(this, remainder_.begin());
                }

                const_iterator end() const {
                    return const_iterator(this, remainder_.end());
                }

            private:
                class ConstIter : public std::iterator<std::input_iterator_tag,
                        value_type,
                        ptrdiff_t,
                        const value_type *,
                        const value_type &> {
                public:
                    ConstIter(const Streamlike *s,
                              typename std::list<value_type>::iterator pos)
                            : s_(s), pos_(pos) {}

                    const value_type &operator*() const { return *pos_; }

                    const value_type *operator->() const { return &*pos_; }

                    ConstIter &operator++() {
                        s_->remainder_.erase(pos_++);
                        return *this;
                    }

                    // *iter++ is required to work (see std::istreambuf_iterator).
                    // (void)iter++ is also required to work.
                    class PostIncrProxy {
                    public:
                        explicit PostIncrProxy(const value_type &value) : value_(value) {}

                        value_type operator*() const { return value_; }

                    private:
                        value_type value_;
                    };

                    PostIncrProxy operator++(int) {
                        PostIncrProxy proxy(**this);
                        ++(*this);
                        return proxy;
                    }

                    friend bool operator==(const ConstIter &a, const ConstIter &b) {
                        return a.s_ == b.s_ && a.pos_ == b.pos_;
                    }

                    friend bool operator!=(const ConstIter &a, const ConstIter &b) {
                        return !(a == b);
                    }

                private:
                    const Streamlike *s_;
                    typename std::list<value_type>::iterator pos_;
                };

                friend std::ostream &operator<<(std::ostream &os, const Streamlike &s) {
                    os << "[";
                    typedef typename std::list<value_type>::const_iterator Iter;
                    const char *sep = "";
                    for (Iter it = s.remainder_.begin(); it != s.remainder_.end(); ++it) {
                        os << sep << *it;
                        sep = ",";
                    }
                    os << "]";
                    return os;
                }

                mutable std::list<value_type> remainder_;  // modified by iteration
            };

            TEST(StreamlikeTest, Iteration) {
                const int a[5] = {2, 1, 4, 5, 3};
                Streamlike<int> s(a, a + 5);
                Streamlike<int>::const_iterator it = s.begin();
                const int *ip = a;
                while (it != s.end()) {
                    SCOPED_TRACE(ip - a);
                    EXPECT_EQ(*ip++, *it++);
                }
            }

            TEST(BeginEndDistanceIsTest, WorksWithForwardList) {
                std::forward_list<int> container;
                EXPECT_THAT(container, BeginEndDistanceIs(0));
                EXPECT_THAT(container, Not(BeginEndDistanceIs(1)));
                container.push_front(0);
                EXPECT_THAT(container, Not(BeginEndDistanceIs(0)));
                EXPECT_THAT(container, BeginEndDistanceIs(1));
                container.push_front(0);
                EXPECT_THAT(container, Not(BeginEndDistanceIs(0)));
                EXPECT_THAT(container, BeginEndDistanceIs(2));
            }

            TEST(BeginEndDistanceIsTest, WorksWithNonStdList) {
                const int a[5] = {1, 2, 3, 4, 5};
                Streamlike<int> s(a, a + 5);
                EXPECT_THAT(s, BeginEndDistanceIs(5));
            }

            TEST(BeginEndDistanceIsTest, CanDescribeSelf) {
                Matcher<vector<int> > m = BeginEndDistanceIs(2);
                EXPECT_EQ("distance between begin() and end() is equal to 2", Describe(m));
                EXPECT_EQ("distance between begin() and end() isn't equal to 2",
                          DescribeNegation(m));
            }

            TEST(BeginEndDistanceIsTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(BeginEndDistanceIs(2)));
                helper.Call(MakeUniquePtrs({1, 2}));
            }

            TEST(BeginEndDistanceIsTest, ExplainsResult) {
                Matcher<vector<int> > m1 = BeginEndDistanceIs(2);
                Matcher<vector<int> > m2 = BeginEndDistanceIs(Lt(2));
                Matcher<vector<int> > m3 = BeginEndDistanceIs(AnyOf(0, 3));
                Matcher<vector<int> > m4 = BeginEndDistanceIs(GreaterThan(1));
                vector<int> container;
                EXPECT_EQ("whose distance between begin() and end() 0 doesn't match",
                          Explain(m1, container));
                EXPECT_EQ("whose distance between begin() and end() 0 matches",
                          Explain(m2, container));
                EXPECT_EQ("whose distance between begin() and end() 0 matches",
                          Explain(m3, container));
                EXPECT_EQ(
                        "whose distance between begin() and end() 0 doesn't match, which is 1 "
                        "less than 1",
                        Explain(m4, container));
                container.push_back(0);
                container.push_back(0);
                EXPECT_EQ("whose distance between begin() and end() 2 matches",
                          Explain(m1, container));
                EXPECT_EQ("whose distance between begin() and end() 2 doesn't match",
                          Explain(m2, container));
                EXPECT_EQ("whose distance between begin() and end() 2 doesn't match",
                          Explain(m3, container));
                EXPECT_EQ(
                        "whose distance between begin() and end() 2 matches, which is 1 more "
                        "than 1",
                        Explain(m4, container));
            }

            TEST(WhenSortedTest, WorksForStreamlike) {
                // Streamlike 'container' provides only minimal iterator support.
                // Its iterators are tagged with input_iterator_tag.
                const int a[5] = {2, 1, 4, 5, 3};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));
                EXPECT_THAT(s, WhenSorted(ElementsAre(1, 2, 3, 4, 5)));
                EXPECT_THAT(s, Not(WhenSorted(ElementsAre(2, 1, 4, 5, 3))));
            }

            TEST(WhenSortedTest, WorksForVectorConstRefMatcherOnStreamlike) {
                const int a[] = {2, 1, 4, 5, 3};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));
                Matcher<const std::vector<int> &> vector_match = ElementsAre(1, 2, 3, 4, 5);
                EXPECT_THAT(s, WhenSorted(vector_match));
                EXPECT_THAT(s, Not(WhenSorted(ElementsAre(2, 1, 4, 5, 3))));
            }

            TEST(IsSupersetOfTest, WorksForNativeArray) {
                const int subset[] = {1, 4};
                const int superset[] = {1, 2, 4};
                const int disjoint[] = {1, 0, 3};
                EXPECT_THAT(subset, IsSupersetOf(subset));
                EXPECT_THAT(subset, Not(IsSupersetOf(superset)));
                EXPECT_THAT(superset, IsSupersetOf(subset));
                EXPECT_THAT(subset, Not(IsSupersetOf(disjoint)));
                EXPECT_THAT(disjoint, Not(IsSupersetOf(subset)));
            }

            TEST(IsSupersetOfTest, WorksWithDuplicates) {
                const int not_enough[] = {1, 2};
                const int enough[] = {1, 1, 2};
                const int expected[] = {1, 1};
                EXPECT_THAT(not_enough, Not(IsSupersetOf(expected)));
                EXPECT_THAT(enough, IsSupersetOf(expected));
            }

            TEST(IsSupersetOfTest, WorksForEmpty) {
                vector<int> numbers;
                vector<int> expected;
                EXPECT_THAT(numbers, IsSupersetOf(expected));
                expected.push_back(1);
                EXPECT_THAT(numbers, Not(IsSupersetOf(expected)));
                expected.clear();
                numbers.push_back(1);
                numbers.push_back(2);
                EXPECT_THAT(numbers, IsSupersetOf(expected));
                expected.push_back(1);
                EXPECT_THAT(numbers, IsSupersetOf(expected));
                expected.push_back(2);
                EXPECT_THAT(numbers, IsSupersetOf(expected));
                expected.push_back(3);
                EXPECT_THAT(numbers, Not(IsSupersetOf(expected)));
            }

            TEST(IsSupersetOfTest, WorksForStreamlike) {
                const int a[5] = {1, 2, 3, 4, 5};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));

                vector<int> expected;
                expected.push_back(1);
                expected.push_back(2);
                expected.push_back(5);
                EXPECT_THAT(s, IsSupersetOf(expected));

                expected.push_back(0);
                EXPECT_THAT(s, Not(IsSupersetOf(expected)));
            }

            TEST(IsSupersetOfTest, TakesStlContainer) {
                const int actual[] = {3, 1, 2};

                ::std::list<int> expected;
                expected.push_back(1);
                expected.push_back(3);
                EXPECT_THAT(actual, IsSupersetOf(expected));

                expected.push_back(4);
                EXPECT_THAT(actual, Not(IsSupersetOf(expected)));
            }

            TEST(IsSupersetOfTest, Describe) {
                typedef std::vector<int> IntVec;
                IntVec expected;
                expected.push_back(111);
                expected.push_back(222);
                expected.push_back(333);
                EXPECT_THAT(
                        Describe<IntVec>(IsSupersetOf(expected)),
                        Eq("a surjection from elements to requirements exists such that:\n"
                           " - an element is equal to 111\n"
                           " - an element is equal to 222\n"
                           " - an element is equal to 333"));
            }

            TEST(IsSupersetOfTest, DescribeNegation) {
                typedef std::vector<int> IntVec;
                IntVec expected;
                expected.push_back(111);
                expected.push_back(222);
                expected.push_back(333);
                EXPECT_THAT(
                        DescribeNegation<IntVec>(IsSupersetOf(expected)),
                        Eq("no surjection from elements to requirements exists such that:\n"
                           " - an element is equal to 111\n"
                           " - an element is equal to 222\n"
                           " - an element is equal to 333"));
            }

            TEST(IsSupersetOfTest, MatchAndExplain) {
                std::vector<int> v;
                v.push_back(2);
                v.push_back(3);
                std::vector<int> expected;
                expected.push_back(1);
                expected.push_back(2);
                StringMatchResultListener listener;
                ASSERT_FALSE(ExplainMatchResult(IsSupersetOf(expected), v, &listener))
                                            << listener.str();
                EXPECT_THAT(listener.str(),
                            Eq("where the following matchers don't match any elements:\n"
                               "matcher #0: is equal to 1"));

                v.push_back(1);
                listener.Clear();
                ASSERT_TRUE(ExplainMatchResult(IsSupersetOf(expected), v, &listener))
                                            << listener.str();
                EXPECT_THAT(listener.str(), Eq("where:\n"
                                               " - element #0 is matched by matcher #1,\n"
                                               " - element #2 is matched by matcher #0"));
            }

            TEST(IsSupersetOfTest, WorksForRhsInitializerList) {
                const int numbers[] = {1, 3, 6, 2, 4, 5};
                EXPECT_THAT(numbers, IsSupersetOf({1, 2}));
                EXPECT_THAT(numbers, Not(IsSupersetOf({3, 0})));
            }

            TEST(IsSupersetOfTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(IsSupersetOf({Pointee(1)})));
                helper.Call(MakeUniquePtrs({1, 2}));
                EXPECT_CALL(helper, Call(Not(IsSupersetOf({Pointee(1), Pointee(2)}))));
                helper.Call(MakeUniquePtrs({2}));
            }

            TEST(IsSubsetOfTest, WorksForNativeArray) {
                const int subset[] = {1, 4};
                const int superset[] = {1, 2, 4};
                const int disjoint[] = {1, 0, 3};
                EXPECT_THAT(subset, IsSubsetOf(subset));
                EXPECT_THAT(subset, IsSubsetOf(superset));
                EXPECT_THAT(superset, Not(IsSubsetOf(subset)));
                EXPECT_THAT(subset, Not(IsSubsetOf(disjoint)));
                EXPECT_THAT(disjoint, Not(IsSubsetOf(subset)));
            }

            TEST(IsSubsetOfTest, WorksWithDuplicates) {
                const int not_enough[] = {1, 2};
                const int enough[] = {1, 1, 2};
                const int actual[] = {1, 1};
                EXPECT_THAT(actual, Not(IsSubsetOf(not_enough)));
                EXPECT_THAT(actual, IsSubsetOf(enough));
            }

            TEST(IsSubsetOfTest, WorksForEmpty) {
                vector<int> numbers;
                vector<int> expected;
                EXPECT_THAT(numbers, IsSubsetOf(expected));
                expected.push_back(1);
                EXPECT_THAT(numbers, IsSubsetOf(expected));
                expected.clear();
                numbers.push_back(1);
                numbers.push_back(2);
                EXPECT_THAT(numbers, Not(IsSubsetOf(expected)));
                expected.push_back(1);
                EXPECT_THAT(numbers, Not(IsSubsetOf(expected)));
                expected.push_back(2);
                EXPECT_THAT(numbers, IsSubsetOf(expected));
                expected.push_back(3);
                EXPECT_THAT(numbers, IsSubsetOf(expected));
            }

            TEST(IsSubsetOfTest, WorksForStreamlike) {
                const int a[5] = {1, 2};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));

                vector<int> expected;
                expected.push_back(1);
                EXPECT_THAT(s, Not(IsSubsetOf(expected)));
                expected.push_back(2);
                expected.push_back(5);
                EXPECT_THAT(s, IsSubsetOf(expected));
            }

            TEST(IsSubsetOfTest, TakesStlContainer) {
                const int actual[] = {3, 1, 2};

                ::std::list<int> expected;
                expected.push_back(1);
                expected.push_back(3);
                EXPECT_THAT(actual, Not(IsSubsetOf(expected)));

                expected.push_back(2);
                expected.push_back(4);
                EXPECT_THAT(actual, IsSubsetOf(expected));
            }

            TEST(IsSubsetOfTest, Describe) {
                typedef std::vector<int> IntVec;
                IntVec expected;
                expected.push_back(111);
                expected.push_back(222);
                expected.push_back(333);

                EXPECT_THAT(
                        Describe<IntVec>(IsSubsetOf(expected)),
                        Eq("an injection from elements to requirements exists such that:\n"
                           " - an element is equal to 111\n"
                           " - an element is equal to 222\n"
                           " - an element is equal to 333"));
            }

            TEST(IsSubsetOfTest, DescribeNegation) {
                typedef std::vector<int> IntVec;
                IntVec expected;
                expected.push_back(111);
                expected.push_back(222);
                expected.push_back(333);
                EXPECT_THAT(
                        DescribeNegation<IntVec>(IsSubsetOf(expected)),
                        Eq("no injection from elements to requirements exists such that:\n"
                           " - an element is equal to 111\n"
                           " - an element is equal to 222\n"
                           " - an element is equal to 333"));
            }

            TEST(IsSubsetOfTest, MatchAndExplain) {
                std::vector<int> v;
                v.push_back(2);
                v.push_back(3);
                std::vector<int> expected;
                expected.push_back(1);
                expected.push_back(2);
                StringMatchResultListener listener;
                ASSERT_FALSE(ExplainMatchResult(IsSubsetOf(expected), v, &listener))
                                            << listener.str();
                EXPECT_THAT(listener.str(),
                            Eq("where the following elements don't match any matchers:\n"
                               "element #1: 3"));

                expected.push_back(3);
                listener.Clear();
                ASSERT_TRUE(ExplainMatchResult(IsSubsetOf(expected), v, &listener))
                                            << listener.str();
                EXPECT_THAT(listener.str(), Eq("where:\n"
                                               " - element #0 is matched by matcher #1,\n"
                                               " - element #1 is matched by matcher #2"));
            }

            TEST(IsSubsetOfTest, WorksForRhsInitializerList) {
                const int numbers[] = {1, 2, 3};
                EXPECT_THAT(numbers, IsSubsetOf({1, 2, 3, 4}));
                EXPECT_THAT(numbers, Not(IsSubsetOf({1, 2})));
            }

            TEST(IsSubsetOfTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(IsSubsetOf({Pointee(1), Pointee(2)})));
                helper.Call(MakeUniquePtrs({1}));
                EXPECT_CALL(helper, Call(Not(IsSubsetOf({Pointee(1)}))));
                helper.Call(MakeUniquePtrs({2}));
            }

// Tests using ElementsAre() and ElementsAreArray() with stream-like
// "containers".

            TEST(ElemensAreStreamTest, WorksForStreamlike) {
                const int a[5] = {1, 2, 3, 4, 5};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));
                EXPECT_THAT(s, ElementsAre(1, 2, 3, 4, 5));
                EXPECT_THAT(s, Not(ElementsAre(2, 1, 4, 5, 3)));
            }

            TEST(ElemensAreArrayStreamTest, WorksForStreamlike) {
                const int a[5] = {1, 2, 3, 4, 5};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));

                vector<int> expected;
                expected.push_back(1);
                expected.push_back(2);
                expected.push_back(3);
                expected.push_back(4);
                expected.push_back(5);
                EXPECT_THAT(s, ElementsAreArray(expected));

                expected[3] = 0;
                EXPECT_THAT(s, Not(ElementsAreArray(expected)));
            }

            TEST(ElementsAreTest, WorksWithUncopyable) {
                Uncopyable objs[2];
                objs[0].set_value(-3);
                objs[1].set_value(1);
                EXPECT_THAT(objs, ElementsAre(UncopyableIs(-3), Truly(ValueIsPositive)));
            }

            TEST(ElementsAreTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(ElementsAre(Pointee(1), Pointee(2))));
                helper.Call(MakeUniquePtrs({1, 2}));

                EXPECT_CALL(helper, Call(ElementsAreArray({Pointee(3), Pointee(4)})));
                helper.Call(MakeUniquePtrs({3, 4}));
            }

            TEST(ElementsAreTest, TakesStlContainer) {
                const int actual[] = {3, 1, 2};

                ::std::list<int> expected;
                expected.push_back(3);
                expected.push_back(1);
                expected.push_back(2);
                EXPECT_THAT(actual, ElementsAreArray(expected));

                expected.push_back(4);
                EXPECT_THAT(actual, Not(ElementsAreArray(expected)));
            }

// Tests for UnorderedElementsAreArray()

            TEST(UnorderedElementsAreArrayTest, SucceedsWhenExpected) {
                const int a[] = {0, 1, 2, 3, 4};
                std::vector<int> s(a, a + GTEST_ARRAY_SIZE_(a));
                do {
                    StringMatchResultListener listener;
                    EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(a),
                                                   s, &listener)) << listener.str();
                } while (std::next_permutation(s.begin(), s.end()));
            }

            TEST(UnorderedElementsAreArrayTest, VectorBool) {
                const bool a[] = {0, 1, 0, 1, 1};
                const bool b[] = {1, 0, 1, 1, 0};
                std::vector<bool> expected(a, a + GTEST_ARRAY_SIZE_(a));
                std::vector<bool> actual(b, b + GTEST_ARRAY_SIZE_(b));
                StringMatchResultListener listener;
                EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(expected),
                                               actual, &listener)) << listener.str();
            }

            TEST(UnorderedElementsAreArrayTest, WorksForStreamlike) {
                // Streamlike 'container' provides only minimal iterator support.
                // Its iterators are tagged with input_iterator_tag, and it has no
                // size() or empty() methods.
                const int a[5] = {2, 1, 4, 5, 3};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));

                ::std::vector<int> expected;
                expected.push_back(1);
                expected.push_back(2);
                expected.push_back(3);
                expected.push_back(4);
                expected.push_back(5);
                EXPECT_THAT(s, UnorderedElementsAreArray(expected));

                expected.push_back(6);
                EXPECT_THAT(s, Not(UnorderedElementsAreArray(expected)));
            }

            TEST(UnorderedElementsAreArrayTest, TakesStlContainer) {
                const int actual[] = {3, 1, 2};

                ::std::list<int> expected;
                expected.push_back(1);
                expected.push_back(2);
                expected.push_back(3);
                EXPECT_THAT(actual, UnorderedElementsAreArray(expected));

                expected.push_back(4);
                EXPECT_THAT(actual, Not(UnorderedElementsAreArray(expected)));
            }


            TEST(UnorderedElementsAreArrayTest, TakesInitializerList) {
                const int a[5] = {2, 1, 4, 5, 3};
                EXPECT_THAT(a, UnorderedElementsAreArray({1, 2, 3, 4, 5}));
                EXPECT_THAT(a, Not(UnorderedElementsAreArray({1, 2, 3, 4, 6})));
            }

            TEST(UnorderedElementsAreArrayTest, TakesInitializerListOfCStrings) {
                const std::string a[5] = {"a", "b", "c", "d", "e"};
                EXPECT_THAT(a, UnorderedElementsAreArray({"a", "b", "c", "d", "e"}));
                EXPECT_THAT(a, Not(UnorderedElementsAreArray({"a", "b", "c", "d", "ef"})));
            }

            TEST(UnorderedElementsAreArrayTest, TakesInitializerListOfSameTypedMatchers) {
                const int a[5] = {2, 1, 4, 5, 3};
                EXPECT_THAT(a, UnorderedElementsAreArray(
                        {Eq(1), Eq(2), Eq(3), Eq(4), Eq(5)}));
                EXPECT_THAT(a, Not(UnorderedElementsAreArray(
                        {Eq(1), Eq(2), Eq(3), Eq(4), Eq(6)})));
            }

            TEST(UnorderedElementsAreArrayTest,
                 TakesInitializerListOfDifferentTypedMatchers) {
                const int a[5] = {2, 1, 4, 5, 3};
                // The compiler cannot infer the type of the initializer list if its
                // elements have different types.  We must explicitly specify the
                // unified element type in this case.
                EXPECT_THAT(a, UnorderedElementsAreArray<Matcher<int> >(
                        {Eq(1), Ne(-2), Ge(3), Le(4), Eq(5)}));
                EXPECT_THAT(a, Not(UnorderedElementsAreArray<Matcher<int> >(
                        {Eq(1), Ne(-2), Ge(3), Le(4), Eq(6)})));
            }


            TEST(UnorderedElementsAreArrayTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper,
                            Call(UnorderedElementsAreArray({Pointee(1), Pointee(2)})));
                helper.Call(MakeUniquePtrs({2, 1}));
            }

            class UnorderedElementsAreTest : public testing::Test {
            protected:
                typedef std::vector<int> IntVec;
            };

            TEST_F(UnorderedElementsAreTest, WorksWithUncopyable) {
                Uncopyable objs[2];
                objs[0].set_value(-3);
                objs[1].set_value(1);
                EXPECT_THAT(objs,
                            UnorderedElementsAre(Truly(ValueIsPositive), UncopyableIs(-3)));
            }

            TEST_F(UnorderedElementsAreTest, SucceedsWhenExpected) {
                const int a[] = {1, 2, 3};
                std::vector<int> s(a, a + GTEST_ARRAY_SIZE_(a));
                do {
                    StringMatchResultListener listener;
                    EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAre(1, 2, 3),
                                                   s, &listener)) << listener.str();
                } while (std::next_permutation(s.begin(), s.end()));
            }

            TEST_F(UnorderedElementsAreTest, FailsWhenAnElementMatchesNoMatcher) {
                const int a[] = {1, 2, 3};
                std::vector<int> s(a, a + GTEST_ARRAY_SIZE_(a));
                std::vector<Matcher<int> > mv;
                mv.push_back(1);
                mv.push_back(2);
                mv.push_back(2);
                // The element with value '3' matches nothing: fail fast.
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAreArray(mv),
                                                s, &listener)) << listener.str();
            }

            TEST_F(UnorderedElementsAreTest, WorksForStreamlike) {
                // Streamlike 'container' provides only minimal iterator support.
                // Its iterators are tagged with input_iterator_tag, and it has no
                // size() or empty() methods.
                const int a[5] = {2, 1, 4, 5, 3};
                Streamlike<int> s(a, a + GTEST_ARRAY_SIZE_(a));

                EXPECT_THAT(s, UnorderedElementsAre(1, 2, 3, 4, 5));
                EXPECT_THAT(s, Not(UnorderedElementsAre(2, 2, 3, 4, 5)));
            }

            TEST_F(UnorderedElementsAreTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(UnorderedElementsAre(Pointee(1), Pointee(2))));
                helper.Call(MakeUniquePtrs({2, 1}));
            }

// One naive implementation of the matcher runs in O(N!) time, which is too
// slow for many real-world inputs. This test shows that our matcher can match
// 100 inputs very quickly (a few milliseconds).  An O(100!) is 10^158
// iterations and obviously effectively incomputable.
// [ RUN      ] UnorderedElementsAreTest.Performance
// [       OK ] UnorderedElementsAreTest.Performance (4 ms)
            TEST_F(UnorderedElementsAreTest, Performance) {
                std::vector<int> s;
                std::vector<Matcher<int> > mv;
                for (int i = 0; i < 100; ++i) {
                    s.push_back(i);
                    mv.push_back(_);
                }
                mv[50] = Eq(0);
                StringMatchResultListener listener;
                EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(mv),
                                               s, &listener)) << listener.str();
            }

// Another variant of 'Performance' with similar expectations.
// [ RUN      ] UnorderedElementsAreTest.PerformanceHalfStrict
// [       OK ] UnorderedElementsAreTest.PerformanceHalfStrict (4 ms)
            TEST_F(UnorderedElementsAreTest, PerformanceHalfStrict) {
                std::vector<int> s;
                std::vector<Matcher<int> > mv;
                for (int i = 0; i < 100; ++i) {
                    s.push_back(i);
                    if (i & 1) {
                        mv.push_back(_);
                    } else {
                        mv.push_back(i);
                    }
                }
                StringMatchResultListener listener;
                EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(mv),
                                               s, &listener)) << listener.str();
            }

            TEST_F(UnorderedElementsAreTest, FailMessageCountWrong) {
                std::vector<int> v;
                v.push_back(4);
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2, 3),
                                                v, &listener)) << listener.str();
                EXPECT_THAT(listener.str(), Eq("which has 1 element"));
            }

            TEST_F(UnorderedElementsAreTest, FailMessageCountWrongZero) {
                std::vector<int> v;
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2, 3),
                                                v, &listener)) << listener.str();
                EXPECT_THAT(listener.str(), Eq(""));
            }

            TEST_F(UnorderedElementsAreTest, FailMessageUnmatchedMatchers) {
                std::vector<int> v;
                v.push_back(1);
                v.push_back(1);
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2),
                                                v, &listener)) << listener.str();
                EXPECT_THAT(
                        listener.str(),
                        Eq("where the following matchers don't match any elements:\n"
                           "matcher #1: is equal to 2"));
            }

            TEST_F(UnorderedElementsAreTest, FailMessageUnmatchedElements) {
                std::vector<int> v;
                v.push_back(1);
                v.push_back(2);
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 1),
                                                v, &listener)) << listener.str();
                EXPECT_THAT(
                        listener.str(),
                        Eq("where the following elements don't match any matchers:\n"
                           "element #1: 2"));
            }

            TEST_F(UnorderedElementsAreTest, FailMessageUnmatchedMatcherAndElement) {
                std::vector<int> v;
                v.push_back(2);
                v.push_back(3);
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2),
                                                v, &listener)) << listener.str();
                EXPECT_THAT(
                        listener.str(),
                        Eq("where"
                           " the following matchers don't match any elements:\n"
                           "matcher #0: is equal to 1\n"
                           "and"
                           " where"
                           " the following elements don't match any matchers:\n"
                           "element #1: 3"));
            }

// Test helper for formatting element, matcher index pairs in expectations.
            static std::string EMString(int element, int matcher) {
                stringstream ss;
                ss << "(element #" << element << ", matcher #" << matcher << ")";
                return ss.str();
            }

            TEST_F(UnorderedElementsAreTest, FailMessageImperfectMatchOnly) {
                // A situation where all elements and matchers have a match
                // associated with them, but the max matching is not perfect.
                std::vector<std::string> v;
                v.push_back("a");
                v.push_back("b");
                v.push_back("c");
                StringMatchResultListener listener;
                EXPECT_FALSE(ExplainMatchResult(
                        UnorderedElementsAre("a", "a", AnyOf("b", "c")), v, &listener))
                                    << listener.str();

                std::string prefix =
                        "where no permutation of the elements can satisfy all matchers, "
                        "and the closest match is 2 of 3 matchers with the "
                        "pairings:\n";

                // We have to be a bit loose here, because there are 4 valid max matches.
                EXPECT_THAT(
                        listener.str(),
                        AnyOf(prefix + "{\n  " + EMString(0, 0) +
                              ",\n  " + EMString(1, 2) + "\n}",
                              prefix + "{\n  " + EMString(0, 1) +
                              ",\n  " + EMString(1, 2) + "\n}",
                              prefix + "{\n  " + EMString(0, 0) +
                              ",\n  " + EMString(2, 2) + "\n}",
                              prefix + "{\n  " + EMString(0, 1) +
                              ",\n  " + EMString(2, 2) + "\n}"));
            }

            TEST_F(UnorderedElementsAreTest, Describe) {
                EXPECT_THAT(Describe<IntVec>(UnorderedElementsAre()),
                            Eq("is empty"));
                EXPECT_THAT(
                        Describe<IntVec>(UnorderedElementsAre(345)),
                        Eq("has 1 element and that element is equal to 345"));
                EXPECT_THAT(
                        Describe<IntVec>(UnorderedElementsAre(111, 222, 333)),
                        Eq("has 3 elements and there exists some permutation "
                           "of elements such that:\n"
                           " - element #0 is equal to 111, and\n"
                           " - element #1 is equal to 222, and\n"
                           " - element #2 is equal to 333"));
            }

            TEST_F(UnorderedElementsAreTest, DescribeNegation) {
                EXPECT_THAT(DescribeNegation<IntVec>(UnorderedElementsAre()),
                            Eq("isn't empty"));
                EXPECT_THAT(
                        DescribeNegation<IntVec>(UnorderedElementsAre(345)),
                        Eq("doesn't have 1 element, or has 1 element that isn't equal to 345"));
                EXPECT_THAT(
                        DescribeNegation<IntVec>(UnorderedElementsAre(123, 234, 345)),
                        Eq("doesn't have 3 elements, or there exists no permutation "
                           "of elements such that:\n"
                           " - element #0 is equal to 123, and\n"
                           " - element #1 is equal to 234, and\n"
                           " - element #2 is equal to 345"));
            }

            namespace {

// Used as a check on the more complex max flow method used in the
// real testing::internal::FindMaxBipartiteMatching. This method is
// compatible but runs in worst-case factorial time, so we only
// use it in testing for small problem sizes.
                template<typename Graph>
                class BacktrackingMaxBPMState {
                public:
                    // Does not take ownership of 'g'.
                    explicit BacktrackingMaxBPMState(const Graph *g) : graph_(g) {}

                    ElementMatcherPairs Compute() {
                        if (graph_->LhsSize() == 0 || graph_->RhsSize() == 0) {
                            return best_so_far_;
                        }
                        lhs_used_.assign(graph_->LhsSize(), kUnused);
                        rhs_used_.assign(graph_->RhsSize(), kUnused);
                        for (size_t irhs = 0; irhs < graph_->RhsSize(); ++irhs) {
                            matches_.clear();
                            RecurseInto(irhs);
                            if (best_so_far_.size() == graph_->RhsSize())
                                break;
                        }
                        return best_so_far_;
                    }

                private:
                    static const size_t kUnused = static_cast<size_t>(-1);

                    void PushMatch(size_t lhs, size_t rhs) {
                        matches_.push_back(ElementMatcherPair(lhs, rhs));
                        lhs_used_[lhs] = rhs;
                        rhs_used_[rhs] = lhs;
                        if (matches_.size() > best_so_far_.size()) {
                            best_so_far_ = matches_;
                        }
                    }

                    void PopMatch() {
                        const ElementMatcherPair &back = matches_.back();
                        lhs_used_[back.first] = kUnused;
                        rhs_used_[back.second] = kUnused;
                        matches_.pop_back();
                    }

                    bool RecurseInto(size_t irhs) {
                        if (rhs_used_[irhs] != kUnused) {
                            return true;
                        }
                        for (size_t ilhs = 0; ilhs < graph_->LhsSize(); ++ilhs) {
                            if (lhs_used_[ilhs] != kUnused) {
                                continue;
                            }
                            if (!graph_->HasEdge(ilhs, irhs)) {
                                continue;
                            }
                            PushMatch(ilhs, irhs);
                            if (best_so_far_.size() == graph_->RhsSize()) {
                                return false;
                            }
                            for (size_t mi = irhs + 1; mi < graph_->RhsSize(); ++mi) {
                                if (!RecurseInto(mi)) return false;
                            }
                            PopMatch();
                        }
                        return true;
                    }

                    const Graph *graph_;  // not owned
                    std::vector<size_t> lhs_used_;
                    std::vector<size_t> rhs_used_;
                    ElementMatcherPairs matches_;
                    ElementMatcherPairs best_so_far_;
                };

                template<typename Graph>
                const size_t BacktrackingMaxBPMState<Graph>::kUnused;

            }  // namespace

// Implement a simple backtracking algorithm to determine if it is possible
// to find one element per matcher, without reusing elements.
            template<typename Graph>
            ElementMatcherPairs
            FindBacktrackingMaxBPM(const Graph &g) {
                return BacktrackingMaxBPMState<Graph>(&g).Compute();
            }

            class BacktrackingBPMTest : public ::testing::Test {
            };

// Tests the MaxBipartiteMatching algorithm with square matrices.
// The single int param is the # of nodes on each of the left and right sides.
            class BipartiteTest : public ::testing::TestWithParam<size_t> {
            };

// Verify all match graphs up to some moderate number of edges.
            TEST_P(BipartiteTest, Exhaustive) {
                size_t nodes = GetParam();
                MatchMatrix graph(nodes, nodes);
                do {
                    ElementMatcherPairs matches =
                            internal::FindMaxBipartiteMatching(graph);
                    EXPECT_EQ(FindBacktrackingMaxBPM(graph).size(), matches.size())
                                        << "graph: " << graph.DebugString();
                    // Check that all elements of matches are in the graph.
                    // Check that elements of first and second are unique.
                    std::vector<bool> seen_element(graph.LhsSize());
                    std::vector<bool> seen_matcher(graph.RhsSize());
                    SCOPED_TRACE(PrintToString(matches));
                    for (size_t i = 0; i < matches.size(); ++i) {
                        size_t ilhs = matches[i].first;
                        size_t irhs = matches[i].second;
                        EXPECT_TRUE(graph.HasEdge(ilhs, irhs));
                        EXPECT_FALSE(seen_element[ilhs]);
                        EXPECT_FALSE(seen_matcher[irhs]);
                        seen_element[ilhs] = true;
                        seen_matcher[irhs] = true;
                    }
                } while (graph.NextGraph());
            }

            INSTANTIATE_TEST_SUITE_P(AllGraphs, BipartiteTest,
                                     ::testing::Range(size_t{0}, size_t{5}));

// Parameterized by a pair interpreted as (LhsSize, RhsSize).
            class BipartiteNonSquareTest
                    : public ::testing::TestWithParam<std::pair<size_t, size_t> > {
            };

            TEST_F(BipartiteNonSquareTest, SimpleBacktracking) {
                //   .......
                // 0:-----\ :
                // 1:---\ | :
                // 2:---\ | :
                // 3:-\ | | :
                //  :.......:
                //    0 1 2
                MatchMatrix g(4, 3);
                static const size_t kEdges[][2] = {{0, 2},
                                                   {1, 1},
                                                   {2, 1},
                                                   {3, 0}};
                for (size_t i = 0; i < GTEST_ARRAY_SIZE_(kEdges); ++i) {
                    g.SetEdge(kEdges[i][0], kEdges[i][1], true);
                }
                EXPECT_THAT(FindBacktrackingMaxBPM(g),
                            ElementsAre(Pair(3, 0),
                                        Pair(AnyOf(1, 2), 1),
                                        Pair(0, 2))) << g.DebugString();
            }

// Verify a few nonsquare matrices.
            TEST_P(BipartiteNonSquareTest, Exhaustive) {
                size_t nlhs = GetParam().first;
                size_t nrhs = GetParam().second;
                MatchMatrix graph(nlhs, nrhs);
                do {
                    EXPECT_EQ(FindBacktrackingMaxBPM(graph).size(),
                              internal::FindMaxBipartiteMatching(graph).size())
                                        << "graph: " << graph.DebugString()
                                        << "\nbacktracking: "
                                        << PrintToString(FindBacktrackingMaxBPM(graph))
                                        << "\nmax flow: "
                                        << PrintToString(internal::FindMaxBipartiteMatching(graph));
                } while (graph.NextGraph());
            }

            INSTANTIATE_TEST_SUITE_P(AllGraphs, BipartiteNonSquareTest,
                                     testing::Values(
                                             std::make_pair(1, 2),
                                             std::make_pair(2, 1),
                                             std::make_pair(3, 2),
                                             std::make_pair(2, 3),
                                             std::make_pair(4, 1),
                                             std::make_pair(1, 4),
                                             std::make_pair(4, 3),
                                             std::make_pair(3, 4)));

            class BipartiteRandomTest
                    : public ::testing::TestWithParam<std::pair<int, int> > {
            };

// Verifies a large sample of larger graphs.
            TEST_P(BipartiteRandomTest, LargerNets) {
                int nodes = GetParam().first;
                int iters = GetParam().second;
                MatchMatrix graph(static_cast<size_t>(nodes), static_cast<size_t>(nodes));

                auto seed = static_cast<testing::internal::UInt32>(GTEST_FLAG(random_seed));
                if (seed == 0) {
                    seed = static_cast<testing::internal::UInt32>(time(nullptr));
                }

                for (; iters > 0; --iters, ++seed) {
                    srand(static_cast<unsigned int>(seed));
                    graph.Randomize();
                    EXPECT_EQ(FindBacktrackingMaxBPM(graph).size(),
                              internal::FindMaxBipartiteMatching(graph).size())
                                        << " graph: " << graph.DebugString()
                                        << "\nTo reproduce the failure, rerun the test with the flag"
                                           " --" << GTEST_FLAG_PREFIX_ << "random_seed=" << seed;
                }
            }

// Test argument is a std::pair<int, int> representing (nodes, iters).
            INSTANTIATE_TEST_SUITE_P(Samples, BipartiteRandomTest,
                                     testing::Values(
                                             std::make_pair(5, 10000),
                                             std::make_pair(6, 5000),
                                             std::make_pair(7, 2000),
                                             std::make_pair(8, 500),
                                             std::make_pair(9, 100)));

// Tests IsReadableTypeName().

            TEST(IsReadableTypeNameTest, ReturnsTrueForShortNames) {
                EXPECT_TRUE(IsReadableTypeName("int"));
                EXPECT_TRUE(IsReadableTypeName("const unsigned char*"));
                EXPECT_TRUE(IsReadableTypeName("MyMap<int, void*>"));
                EXPECT_TRUE(IsReadableTypeName("void (*)(int, bool)"));
            }

            TEST(IsReadableTypeNameTest, ReturnsTrueForLongNonTemplateNonFunctionNames) {
                EXPECT_TRUE(IsReadableTypeName("my_long_namespace::MyClassName"));
                EXPECT_TRUE(IsReadableTypeName("int [5][6][7][8][9][10][11]"));
                EXPECT_TRUE(IsReadableTypeName("my_namespace::MyOuterClass::MyInnerClass"));
            }

            TEST(IsReadableTypeNameTest, ReturnsFalseForLongTemplateNames) {
                EXPECT_FALSE(
                        IsReadableTypeName("basic_string<char, std::char_traits<char> >"));
                EXPECT_FALSE(IsReadableTypeName("std::vector<int, std::alloc_traits<int> >"));
            }

            TEST(IsReadableTypeNameTest, ReturnsFalseForLongFunctionTypeNames) {
                EXPECT_FALSE(IsReadableTypeName("void (&)(int, bool, char, float)"));
            }

// Tests FormatMatcherDescription().

            TEST(FormatMatcherDescriptionTest, WorksForEmptyDescription) {
                EXPECT_EQ("is even",
                          FormatMatcherDescription(false, "IsEven", Strings()));
                EXPECT_EQ("not (is even)",
                          FormatMatcherDescription(true, "IsEven", Strings()));

                const char *params[] = {"5"};
                EXPECT_EQ("equals 5",
                          FormatMatcherDescription(false, "Equals",
                                                   Strings(params, params + 1)));

                const char *params2[] = {"5", "8"};
                EXPECT_EQ("is in range (5, 8)",
                          FormatMatcherDescription(false, "IsInRange",
                                                   Strings(params2, params2 + 2)));
            }

// Tests PolymorphicMatcher::mutable_impl().
            TEST(PolymorphicMatcherTest, CanAccessMutableImpl) {
                PolymorphicMatcher<DivisibleByImpl> m(DivisibleByImpl(42));
                DivisibleByImpl &impl = m.mutable_impl();
                EXPECT_EQ(42, impl.divider());

                impl.set_divider(0);
                EXPECT_EQ(0, m.mutable_impl().divider());
            }

// Tests PolymorphicMatcher::impl().
            TEST(PolymorphicMatcherTest, CanAccessImpl) {
                const PolymorphicMatcher<DivisibleByImpl> m(DivisibleByImpl(42));
                const DivisibleByImpl &impl = m.impl();
                EXPECT_EQ(42, impl.divider());
            }

            TEST(MatcherTupleTest, ExplainsMatchFailure) {
                stringstream ss1;
                ExplainMatchFailureTupleTo(
                        std::make_tuple(Matcher<char>(Eq('a')), GreaterThan(5)),
                        std::make_tuple('a', 10), &ss1);
                EXPECT_EQ("", ss1.str());  // Successful match.

                stringstream ss2;
                ExplainMatchFailureTupleTo(
                        std::make_tuple(GreaterThan(5), Matcher<char>(Eq('a'))),
                        std::make_tuple(2, 'b'), &ss2);
                EXPECT_EQ("  Expected arg #0: is > 5\n"
                          "           Actual: 2, which is 3 less than 5\n"
                          "  Expected arg #1: is equal to 'a' (97, 0x61)\n"
                          "           Actual: 'b' (98, 0x62)\n",
                          ss2.str());  // Failed match where both arguments need explanation.

                stringstream ss3;
                ExplainMatchFailureTupleTo(
                        std::make_tuple(GreaterThan(5), Matcher<char>(Eq('a'))),
                        std::make_tuple(2, 'a'), &ss3);
                EXPECT_EQ("  Expected arg #0: is > 5\n"
                          "           Actual: 2, which is 3 less than 5\n",
                          ss3.str());  // Failed match where only one argument needs
                // explanation.
            }

// Tests Each().

            TEST(EachTest, ExplainsMatchResultCorrectly) {
                set<int> a;  // empty

                Matcher<set<int> > m = Each(2);
                EXPECT_EQ("", Explain(m, a));

                Matcher<const int (&)[1]> n = Each(1);  // NOLINT

                const int b[1] = {1};
                EXPECT_EQ("", Explain(n, b));

                n = Each(3);
                EXPECT_EQ("whose element #0 doesn't match", Explain(n, b));

                a.insert(1);
                a.insert(2);
                a.insert(3);
                m = Each(GreaterThan(0));
                EXPECT_EQ("", Explain(m, a));

                m = Each(GreaterThan(10));
                EXPECT_EQ("whose element #0 doesn't match, which is 9 less than 10",
                          Explain(m, a));
            }

            TEST(EachTest, DescribesItselfCorrectly) {
                Matcher<vector<int> > m = Each(1);
                EXPECT_EQ("only contains elements that is equal to 1", Describe(m));

                Matcher<vector<int> > m2 = Not(m);
                EXPECT_EQ("contains some element that isn't equal to 1", Describe(m2));
            }

            TEST(EachTest, MatchesVectorWhenAllElementsMatch) {
                vector<int> some_vector;
                EXPECT_THAT(some_vector, Each(1));
                some_vector.push_back(3);
                EXPECT_THAT(some_vector, Not(Each(1)));
                EXPECT_THAT(some_vector, Each(3));
                some_vector.push_back(1);
                some_vector.push_back(2);
                EXPECT_THAT(some_vector, Not(Each(3)));
                EXPECT_THAT(some_vector, Each(Lt(3.5)));

                vector<std::string> another_vector;
                another_vector.push_back("fee");
                EXPECT_THAT(another_vector, Each(std::string("fee")));
                another_vector.push_back("fie");
                another_vector.push_back("foe");
                another_vector.push_back("fum");
                EXPECT_THAT(another_vector, Not(Each(std::string("fee"))));
            }

            TEST(EachTest, MatchesMapWhenAllElementsMatch) {
                map<const char *, int> my_map;
                const char *bar = "a string";
                my_map[bar] = 2;
                EXPECT_THAT(my_map, Each(make_pair(bar, 2)));

                map<std::string, int> another_map;
                EXPECT_THAT(another_map, Each(make_pair(std::string("fee"), 1)));
                another_map["fee"] = 1;
                EXPECT_THAT(another_map, Each(make_pair(std::string("fee"), 1)));
                another_map["fie"] = 2;
                another_map["foe"] = 3;
                another_map["fum"] = 4;
                EXPECT_THAT(another_map, Not(Each(make_pair(std::string("fee"), 1))));
                EXPECT_THAT(another_map, Not(Each(make_pair(std::string("fum"), 1))));
                EXPECT_THAT(another_map, Each(Pair(_, Gt(0))));
            }

            TEST(EachTest, AcceptsMatcher) {
                const int a[] = {1, 2, 3};
                EXPECT_THAT(a, Each(Gt(0)));
                EXPECT_THAT(a, Not(Each(Gt(1))));
            }

            TEST(EachTest, WorksForNativeArrayAsTuple) {
                const int a[] = {1, 2};
                const int *const pointer = a;
                EXPECT_THAT(std::make_tuple(pointer, 2), Each(Gt(0)));
                EXPECT_THAT(std::make_tuple(pointer, 2), Not(Each(Gt(1))));
            }

            TEST(EachTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(Each(Pointee(Gt(0)))));
                helper.Call(MakeUniquePtrs({1, 2}));
            }

// For testing Pointwise().
            class IsHalfOfMatcher {
            public:
                template<typename T1, typename T2>
                bool MatchAndExplain(const std::tuple<T1, T2> &a_pair,
                                     MatchResultListener *listener) const {
                    if (std::get<0>(a_pair) == std::get<1>(a_pair) / 2) {
                        *listener << "where the second is " << std::get<1>(a_pair);
                        return true;
                    } else {
                        *listener << "where the second/2 is " << std::get<1>(a_pair) / 2;
                        return false;
                    }
                }

                void DescribeTo(ostream *os) const {
                    *os << "are a pair where the first is half of the second";
                }

                void DescribeNegationTo(ostream *os) const {
                    *os << "are a pair where the first isn't half of the second";
                }
            };

            PolymorphicMatcher<IsHalfOfMatcher> IsHalfOf() {
                return MakePolymorphicMatcher(IsHalfOfMatcher());
            }

            TEST(PointwiseTest, DescribesSelf) {
                vector<int> rhs;
                rhs.push_back(1);
                rhs.push_back(2);
                rhs.push_back(3);
                const Matcher<const vector<int> &> m = Pointwise(IsHalfOf(), rhs);
                EXPECT_EQ("contains 3 values, where each value and its corresponding value "
                          "in { 1, 2, 3 } are a pair where the first is half of the second",
                          Describe(m));
                EXPECT_EQ("doesn't contain exactly 3 values, or contains a value x at some "
                          "index i where x and the i-th value of { 1, 2, 3 } are a pair "
                          "where the first isn't half of the second",
                          DescribeNegation(m));
            }

            TEST(PointwiseTest, MakesCopyOfRhs) {
                list<signed char> rhs;
                rhs.push_back(2);
                rhs.push_back(4);

                int lhs[] = {1, 2};
                const Matcher<const int (&)[2]> m = Pointwise(IsHalfOf(), rhs);
                EXPECT_THAT(lhs, m);

                // Changing rhs now shouldn't affect m, which made a copy of rhs.
                rhs.push_back(6);
                EXPECT_THAT(lhs, m);
            }

            TEST(PointwiseTest, WorksForLhsNativeArray) {
                const int lhs[] = {1, 2, 3};
                vector<int> rhs;
                rhs.push_back(2);
                rhs.push_back(4);
                rhs.push_back(6);
                EXPECT_THAT(lhs, Pointwise(Lt(), rhs));
                EXPECT_THAT(lhs, Not(Pointwise(Gt(), rhs)));
            }

            TEST(PointwiseTest, WorksForRhsNativeArray) {
                const int rhs[] = {1, 2, 3};
                vector<int> lhs;
                lhs.push_back(2);
                lhs.push_back(4);
                lhs.push_back(6);
                EXPECT_THAT(lhs, Pointwise(Gt(), rhs));
                EXPECT_THAT(lhs, Not(Pointwise(Lt(), rhs)));
            }

// Test is effective only with sanitizers.
            TEST(PointwiseTest, WorksForVectorOfBool) {
                vector<bool> rhs(3, false);
                rhs[1] = true;
                vector<bool> lhs = rhs;
                EXPECT_THAT(lhs, Pointwise(Eq(), rhs));
                rhs[0] = true;
                EXPECT_THAT(lhs, Not(Pointwise(Eq(), rhs)));
            }


            TEST(PointwiseTest, WorksForRhsInitializerList) {
                const vector<int> lhs{2, 4, 6};
                EXPECT_THAT(lhs, Pointwise(Gt(), {1, 2, 3}));
                EXPECT_THAT(lhs, Not(Pointwise(Lt(), {3, 3, 7})));
            }


            TEST(PointwiseTest, RejectsWrongSize) {
                const double lhs[2] = {1, 2};
                const int rhs[1] = {0};
                EXPECT_THAT(lhs, Not(Pointwise(Gt(), rhs)));
                EXPECT_EQ("which contains 2 values",
                          Explain(Pointwise(Gt(), rhs), lhs));

                const int rhs2[3] = {0, 1, 2};
                EXPECT_THAT(lhs, Not(Pointwise(Gt(), rhs2)));
            }

            TEST(PointwiseTest, RejectsWrongContent) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {2, 6, 4};
                EXPECT_THAT(lhs, Not(Pointwise(IsHalfOf(), rhs)));
                EXPECT_EQ("where the value pair (2, 6) at index #1 don't match, "
                          "where the second/2 is 3",
                          Explain(Pointwise(IsHalfOf(), rhs), lhs));
            }

            TEST(PointwiseTest, AcceptsCorrectContent) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {2, 4, 6};
                EXPECT_THAT(lhs, Pointwise(IsHalfOf(), rhs));
                EXPECT_EQ("", Explain(Pointwise(IsHalfOf(), rhs), lhs));
            }

            TEST(PointwiseTest, AllowsMonomorphicInnerMatcher) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {2, 4, 6};
                const Matcher<std::tuple<const double &, const int &>> m1 = IsHalfOf();
                EXPECT_THAT(lhs, Pointwise(m1, rhs));
                EXPECT_EQ("", Explain(Pointwise(m1, rhs), lhs));

                // This type works as a std::tuple<const double&, const int&> can be
                // implicitly cast to std::tuple<double, int>.
                const Matcher<std::tuple<double, int>> m2 = IsHalfOf();
                EXPECT_THAT(lhs, Pointwise(m2, rhs));
                EXPECT_EQ("", Explain(Pointwise(m2, rhs), lhs));
            }

            MATCHER(PointeeEquals, "Points to an equal value") {
                return ExplainMatchResult(::testing::Pointee(::testing::get<1>(arg)),
                                          ::testing::get<0>(arg), result_listener);
            }

            TEST(PointwiseTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(Pointwise(PointeeEquals(), std::vector<int>{1, 2})));
                helper.Call(MakeUniquePtrs({1, 2}));
            }

            TEST(UnorderedPointwiseTest, DescribesSelf) {
                vector<int> rhs;
                rhs.push_back(1);
                rhs.push_back(2);
                rhs.push_back(3);
                const Matcher<const vector<int> &> m = UnorderedPointwise(IsHalfOf(), rhs);
                EXPECT_EQ(
                        "has 3 elements and there exists some permutation of elements such "
                        "that:\n"
                        " - element #0 and 1 are a pair where the first is half of the second, "
                        "and\n"
                        " - element #1 and 2 are a pair where the first is half of the second, "
                        "and\n"
                        " - element #2 and 3 are a pair where the first is half of the second",
                        Describe(m));
                EXPECT_EQ(
                        "doesn't have 3 elements, or there exists no permutation of elements "
                        "such that:\n"
                        " - element #0 and 1 are a pair where the first is half of the second, "
                        "and\n"
                        " - element #1 and 2 are a pair where the first is half of the second, "
                        "and\n"
                        " - element #2 and 3 are a pair where the first is half of the second",
                        DescribeNegation(m));
            }

            TEST(UnorderedPointwiseTest, MakesCopyOfRhs) {
                list<signed char> rhs;
                rhs.push_back(2);
                rhs.push_back(4);

                int lhs[] = {2, 1};
                const Matcher<const int (&)[2]> m = UnorderedPointwise(IsHalfOf(), rhs);
                EXPECT_THAT(lhs, m);

                // Changing rhs now shouldn't affect m, which made a copy of rhs.
                rhs.push_back(6);
                EXPECT_THAT(lhs, m);
            }

            TEST(UnorderedPointwiseTest, WorksForLhsNativeArray) {
                const int lhs[] = {1, 2, 3};
                vector<int> rhs;
                rhs.push_back(4);
                rhs.push_back(6);
                rhs.push_back(2);
                EXPECT_THAT(lhs, UnorderedPointwise(Lt(), rhs));
                EXPECT_THAT(lhs, Not(UnorderedPointwise(Gt(), rhs)));
            }

            TEST(UnorderedPointwiseTest, WorksForRhsNativeArray) {
                const int rhs[] = {1, 2, 3};
                vector<int> lhs;
                lhs.push_back(4);
                lhs.push_back(2);
                lhs.push_back(6);
                EXPECT_THAT(lhs, UnorderedPointwise(Gt(), rhs));
                EXPECT_THAT(lhs, Not(UnorderedPointwise(Lt(), rhs)));
            }


            TEST(UnorderedPointwiseTest, WorksForRhsInitializerList) {
                const vector<int> lhs{2, 4, 6};
                EXPECT_THAT(lhs, UnorderedPointwise(Gt(), {5, 1, 3}));
                EXPECT_THAT(lhs, Not(UnorderedPointwise(Lt(), {1, 1, 7})));
            }


            TEST(UnorderedPointwiseTest, RejectsWrongSize) {
                const double lhs[2] = {1, 2};
                const int rhs[1] = {0};
                EXPECT_THAT(lhs, Not(UnorderedPointwise(Gt(), rhs)));
                EXPECT_EQ("which has 2 elements",
                          Explain(UnorderedPointwise(Gt(), rhs), lhs));

                const int rhs2[3] = {0, 1, 2};
                EXPECT_THAT(lhs, Not(UnorderedPointwise(Gt(), rhs2)));
            }

            TEST(UnorderedPointwiseTest, RejectsWrongContent) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {2, 6, 6};
                EXPECT_THAT(lhs, Not(UnorderedPointwise(IsHalfOf(), rhs)));
                EXPECT_EQ("where the following elements don't match any matchers:\n"
                          "element #1: 2",
                          Explain(UnorderedPointwise(IsHalfOf(), rhs), lhs));
            }

            TEST(UnorderedPointwiseTest, AcceptsCorrectContentInSameOrder) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {2, 4, 6};
                EXPECT_THAT(lhs, UnorderedPointwise(IsHalfOf(), rhs));
            }

            TEST(UnorderedPointwiseTest, AcceptsCorrectContentInDifferentOrder) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {6, 4, 2};
                EXPECT_THAT(lhs, UnorderedPointwise(IsHalfOf(), rhs));
            }

            TEST(UnorderedPointwiseTest, AllowsMonomorphicInnerMatcher) {
                const double lhs[3] = {1, 2, 3};
                const int rhs[3] = {4, 6, 2};
                const Matcher<std::tuple<const double &, const int &>> m1 = IsHalfOf();
                EXPECT_THAT(lhs, UnorderedPointwise(m1, rhs));

                // This type works as a std::tuple<const double&, const int&> can be
                // implicitly cast to std::tuple<double, int>.
                const Matcher<std::tuple<double, int>> m2 = IsHalfOf();
                EXPECT_THAT(lhs, UnorderedPointwise(m2, rhs));
            }

            TEST(UnorderedPointwiseTest, WorksWithMoveOnly) {
                ContainerHelper helper;
                EXPECT_CALL(helper, Call(UnorderedPointwise(PointeeEquals(),
                                                            std::vector<int>{1, 2})));
                helper.Call(MakeUniquePtrs({2, 1}));
            }

// Sample optional type implementation with minimal requirements for use with
// Optional matcher.
            template<typename T>
            class SampleOptional {
            public:
                using value_type = T;

                explicit SampleOptional(T value)
                        : value_(std::move(value)), has_value_(true) {}

                SampleOptional() : value_(), has_value_(false) {}

                operator bool() const { return has_value_; }

                const T &operator*() const { return value_; }

            private:
                T value_;
                bool has_value_;
            };

            TEST(OptionalTest, DescribesSelf) {
                const Matcher<SampleOptional<int>> m = Optional(Eq(1));
                EXPECT_EQ("value is equal to 1", Describe(m));
            }

            TEST(OptionalTest, ExplainsSelf) {
                const Matcher<SampleOptional<int>> m = Optional(Eq(1));
                EXPECT_EQ("whose value 1 matches", Explain(m, SampleOptional<int>(1)));
                EXPECT_EQ("whose value 2 doesn't match", Explain(m, SampleOptional<int>(2)));
            }

            TEST(OptionalTest, MatchesNonEmptyOptional) {
                const Matcher<SampleOptional<int>> m1 = Optional(1);
                const Matcher<SampleOptional<int>> m2 = Optional(Eq(2));
                const Matcher<SampleOptional<int>> m3 = Optional(Lt(3));
                SampleOptional<int> opt(1);
                EXPECT_TRUE(m1.Matches(opt));
                EXPECT_FALSE(m2.Matches(opt));
                EXPECT_TRUE(m3.Matches(opt));
            }

            TEST(OptionalTest, DoesNotMatchNullopt) {
                const Matcher<SampleOptional<int>> m = Optional(1);
                SampleOptional<int> empty;
                EXPECT_FALSE(m.Matches(empty));
            }

            TEST(OptionalTest, WorksWithMoveOnly) {
                Matcher<SampleOptional<std::unique_ptr<int>>> m = Optional(Eq(nullptr));
                EXPECT_TRUE(m.Matches(SampleOptional<std::unique_ptr<int>>(nullptr)));
            }

            class SampleVariantIntString {
            public:
                SampleVariantIntString(int i) : i_(i), has_int_(true) {}

                SampleVariantIntString(const std::string &s) : s_(s), has_int_(false) {}

                template<typename T>
                friend bool holds_alternative(const SampleVariantIntString &value) {
                    return value.has_int_ == std::is_same<T, int>::value;
                }

                template<typename T>
                friend const T &get(const SampleVariantIntString &value) {
                    return value.get_impl(static_cast<T *>(nullptr));
                }

            private:
                const int &get_impl(int *) const { return i_; }

                const std::string &get_impl(std::string *) const { return s_; }

                int i_;
                std::string s_;
                bool has_int_;
            };

            TEST(VariantTest, DescribesSelf) {
                const Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
                EXPECT_THAT(Describe(m), ContainsRegex("is a variant<> with value of type "
                                                       "'.*' and the value is equal to 1"));
            }

            TEST(VariantTest, ExplainsSelf) {
                const Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
                EXPECT_THAT(Explain(m, SampleVariantIntString(1)),
                            ContainsRegex("whose value 1"));
                EXPECT_THAT(Explain(m, SampleVariantIntString("A")),
                            HasSubstr("whose value is not of type '"));
                EXPECT_THAT(Explain(m, SampleVariantIntString(2)),
                            "whose value 2 doesn't match");
            }

            TEST(VariantTest, FullMatch) {
                Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
                EXPECT_TRUE(m.Matches(SampleVariantIntString(1)));

                m = VariantWith<std::string>(Eq("1"));
                EXPECT_TRUE(m.Matches(SampleVariantIntString("1")));
            }

            TEST(VariantTest, TypeDoesNotMatch) {
                Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
                EXPECT_FALSE(m.Matches(SampleVariantIntString("1")));

                m = VariantWith<std::string>(Eq("1"));
                EXPECT_FALSE(m.Matches(SampleVariantIntString(1)));
            }

            TEST(VariantTest, InnerDoesNotMatch) {
                Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
                EXPECT_FALSE(m.Matches(SampleVariantIntString(2)));

                m = VariantWith<std::string>(Eq("1"));
                EXPECT_FALSE(m.Matches(SampleVariantIntString("2")));
            }

            class SampleAnyType {
            public:
                explicit SampleAnyType(int i) : index_(0), i_(i) {}

                explicit SampleAnyType(const std::string &s) : index_(1), s_(s) {}

                template<typename T>
                friend const T *any_cast(const SampleAnyType *any) {
                    return any->get_impl(static_cast<T *>(nullptr));
                }

            private:
                int index_;
                int i_;
                std::string s_;

                const int *get_impl(int *) const { return index_ == 0 ? &i_ : nullptr; }

                const std::string *get_impl(std::string *) const {
                    return index_ == 1 ? &s_ : nullptr;
                }
            };

            TEST(AnyWithTest, FullMatch) {
                Matcher<SampleAnyType> m = AnyWith<int>(Eq(1));
                EXPECT_TRUE(m.Matches(SampleAnyType(1)));
            }

            TEST(AnyWithTest, TestBadCastType) {
                Matcher<SampleAnyType> m = AnyWith<std::string>(Eq("fail"));
                EXPECT_FALSE(m.Matches(SampleAnyType(1)));
            }

            TEST(AnyWithTest, TestUseInContainers) {
                std::vector<SampleAnyType> a;
                a.emplace_back(1);
                a.emplace_back(2);
                a.emplace_back(3);
                EXPECT_THAT(
                        a, ElementsAreArray({AnyWith<int>(1), AnyWith<int>(2), AnyWith<int>(3)}));

                std::vector<SampleAnyType> b;
                b.emplace_back("hello");
                b.emplace_back("merhaba");
                b.emplace_back("salut");
                EXPECT_THAT(b, ElementsAreArray({AnyWith<std::string>("hello"),
                                                 AnyWith<std::string>("merhaba"),
                                                 AnyWith<std::string>("salut")}));
            }

            TEST(AnyWithTest, TestCompare) {
                EXPECT_THAT(SampleAnyType(1), AnyWith<int>(Gt(0)));
            }

            TEST(AnyWithTest, DescribesSelf) {
                const Matcher<const SampleAnyType &> m = AnyWith<int>(Eq(1));
                EXPECT_THAT(Describe(m), ContainsRegex("is an 'any' type with value of type "
                                                       "'.*' and the value is equal to 1"));
            }

            TEST(AnyWithTest, ExplainsSelf) {
                const Matcher<const SampleAnyType &> m = AnyWith<int>(Eq(1));

                EXPECT_THAT(Explain(m, SampleAnyType(1)), ContainsRegex("whose value 1"));
                EXPECT_THAT(Explain(m, SampleAnyType("A")),
                            HasSubstr("whose value is not of type '"));
                EXPECT_THAT(Explain(m, SampleAnyType(2)), "whose value 2 doesn't match");
            }

            TEST(PointeeTest, WorksOnMoveOnlyType) {
                std::unique_ptr<int> p(new int(3));
                EXPECT_THAT(p, Pointee(Eq(3)));
                EXPECT_THAT(p, Not(Pointee(Eq(2))));
            }

            TEST(NotTest, WorksOnMoveOnlyType) {
                std::unique_ptr<int> p(new int(3));
                EXPECT_THAT(p, Pointee(Eq(3)));
                EXPECT_THAT(p, Not(Pointee(Eq(2))));
            }

// Tests Args<k0, ..., kn>(m).

            TEST(ArgsTest, AcceptsZeroTemplateArg) {
                const std::tuple<int, bool> t(5, true);
                EXPECT_THAT(t, Args<>(Eq(std::tuple<>())));
                EXPECT_THAT(t, Not(Args<>(Ne(std::tuple<>()))));
            }

            TEST(ArgsTest, AcceptsOneTemplateArg) {
                const std::tuple<int, bool> t(5, true);
                EXPECT_THAT(t, Args<0>(Eq(std::make_tuple(5))));
                EXPECT_THAT(t, Args<1>(Eq(std::make_tuple(true))));
                EXPECT_THAT(t, Not(Args<1>(Eq(std::make_tuple(false)))));
            }

            TEST(ArgsTest, AcceptsTwoTemplateArgs) {
                const std::tuple<short, int, long> t(4, 5, 6L);  // NOLINT

                EXPECT_THAT(t, (Args<0, 1>(Lt())));
                EXPECT_THAT(t, (Args<1, 2>(Lt())));
                EXPECT_THAT(t, Not(Args<0, 2>(Gt())));
            }

            TEST(ArgsTest, AcceptsRepeatedTemplateArgs) {
                const std::tuple<short, int, long> t(4, 5, 6L);  // NOLINT
                EXPECT_THAT(t, (Args<0, 0>(Eq())));
                EXPECT_THAT(t, Not(Args<1, 1>(Ne())));
            }

            TEST(ArgsTest, AcceptsDecreasingTemplateArgs) {
                const std::tuple<short, int, long> t(4, 5, 6L);  // NOLINT
                EXPECT_THAT(t, (Args<2, 0>(Gt())));
                EXPECT_THAT(t, Not(Args<2, 1>(Lt())));
            }

            MATCHER(SumIsZero, "") {
                return std::get<0>(arg) + std::get<1>(arg) + std::get<2>(arg) == 0;
            }

            TEST(ArgsTest, AcceptsMoreTemplateArgsThanArityOfOriginalTuple) {
                EXPECT_THAT(std::make_tuple(-1, 2), (Args<0, 0, 1>(SumIsZero())));
                EXPECT_THAT(std::make_tuple(1, 2), Not(Args<0, 0, 1>(SumIsZero())));
            }

            TEST(ArgsTest, CanBeNested) {
                const std::tuple<short, int, long, int> t(4, 5, 6L, 6);  // NOLINT
                EXPECT_THAT(t, (Args<1, 2, 3>(Args<1, 2>(Eq()))));
                EXPECT_THAT(t, (Args<0, 1, 3>(Args<0, 2>(Lt()))));
            }

            TEST(ArgsTest, CanMatchTupleByValue) {
                typedef std::tuple<char, int, int> Tuple3;
                const Matcher<Tuple3> m = Args<1, 2>(Lt());
                EXPECT_TRUE(m.Matches(Tuple3('a', 1, 2)));
                EXPECT_FALSE(m.Matches(Tuple3('b', 2, 2)));
            }

            TEST(ArgsTest, CanMatchTupleByReference) {
                typedef std::tuple<char, char, int> Tuple3;
                const Matcher<const Tuple3 &> m = Args<0, 1>(Lt());
                EXPECT_TRUE(m.Matches(Tuple3('a', 'b', 2)));
                EXPECT_FALSE(m.Matches(Tuple3('b', 'b', 2)));
            }

// Validates that arg is printed as str.
            MATCHER_P(PrintsAs, str, "") {
                return testing::PrintToString(arg) == str;
            }

            TEST(ArgsTest, AcceptsTenTemplateArgs) {
                EXPECT_THAT(std::make_tuple(0, 1L, 2, 3L, 4, 5, 6, 7, 8, 9),
                            (Args<9, 8, 7, 6, 5, 4, 3, 2, 1, 0>(
                                    PrintsAs("(9, 8, 7, 6, 5, 4, 3, 2, 1, 0)"))));
                EXPECT_THAT(std::make_tuple(0, 1L, 2, 3L, 4, 5, 6, 7, 8, 9),
                            Not(Args<9, 8, 7, 6, 5, 4, 3, 2, 1, 0>(
                                    PrintsAs("(0, 8, 7, 6, 5, 4, 3, 2, 1, 0)"))));
            }

            TEST(ArgsTest, DescirbesSelfCorrectly) {
                const Matcher<std::tuple<int, bool, char> > m = Args<2, 0>(Lt());
                EXPECT_EQ("are a tuple whose fields (#2, #0) are a pair where "
                          "the first < the second",
                          Describe(m));
            }

            TEST(ArgsTest, DescirbesNestedArgsCorrectly) {
                const Matcher<const std::tuple<int, bool, char, int> &> m =
                        Args<0, 2, 3>(Args<2, 0>(Lt()));
                EXPECT_EQ("are a tuple whose fields (#0, #2, #3) are a tuple "
                          "whose fields (#2, #0) are a pair where the first < the second",
                          Describe(m));
            }

            TEST(ArgsTest, DescribesNegationCorrectly) {
                const Matcher<std::tuple<int, char> > m = Args<1, 0>(Gt());
                EXPECT_EQ("are a tuple whose fields (#1, #0) aren't a pair "
                          "where the first > the second",
                          DescribeNegation(m));
            }

            TEST(ArgsTest, ExplainsMatchResultWithoutInnerExplanation) {
                const Matcher<std::tuple<bool, int, int> > m = Args<1, 2>(Eq());
                EXPECT_EQ("whose fields (#1, #2) are (42, 42)",
                          Explain(m, std::make_tuple(false, 42, 42)));
                EXPECT_EQ("whose fields (#1, #2) are (42, 43)",
                          Explain(m, std::make_tuple(false, 42, 43)));
            }

// For testing Args<>'s explanation.
            class LessThanMatcher : public MatcherInterface<std::tuple<char, int> > {
            public:
                void DescribeTo(::std::ostream * /*os*/) const override {}

                bool MatchAndExplain(std::tuple<char, int> value,
                                     MatchResultListener *listener) const override {
                    const int diff = std::get<0>(value) - std::get<1>(value);
                    if (diff > 0) {
                        *listener << "where the first value is " << diff
                                  << " more than the second";
                    }
                    return diff < 0;
                }
            };

            Matcher<std::tuple<char, int> > LessThan() {
                return MakeMatcher(new LessThanMatcher);
            }

            TEST(ArgsTest, ExplainsMatchResultWithInnerExplanation) {
                const Matcher<std::tuple<char, int, int> > m = Args<0, 2>(LessThan());
                EXPECT_EQ(
                        "whose fields (#0, #2) are ('a' (97, 0x61), 42), "
                        "where the first value is 55 more than the second",
                        Explain(m, std::make_tuple('a', 42, 42)));
                EXPECT_EQ("whose fields (#0, #2) are ('\\0', 43)",
                          Explain(m, std::make_tuple('\0', 42, 43)));
            }

            class PredicateFormatterFromMatcherTest : public ::testing::Test {
            protected:
                enum Behavior {
                    kInitialSuccess, kAlwaysFail, kFlaky
                };

                // A matcher that can return different results when used multiple times on the
                // same input. No real matcher should do this; but this lets us test that we
                // detect such behavior and fail appropriately.
                class MockMatcher : public MatcherInterface<Behavior> {
                public:
                    bool MatchAndExplain(Behavior behavior,
                                         MatchResultListener *listener) const override {
                        *listener << "[MatchAndExplain]";
                        switch (behavior) {
                            case kInitialSuccess:
                                // The first call to MatchAndExplain should use a "not interested"
                                // listener; so this is expected to return |true|. There should be no
                                // subsequent calls.
                                return !listener->IsInterested();

                            case kAlwaysFail:
                                return false;

                            case kFlaky:
                                // The first call to MatchAndExplain should use a "not interested"
                                // listener; so this will return |false|. Subsequent calls should have
                                // an "interested" listener; so this will return |true|, thus
                                // simulating a flaky matcher.
                                return listener->IsInterested();
                        }

                        GTEST_LOG_(FATAL) << "This should never be reached";
                        return false;
                    }

                    void DescribeTo(ostream *os) const override { *os << "[DescribeTo]"; }

                    void DescribeNegationTo(ostream *os) const override {
                        *os << "[DescribeNegationTo]";
                    }
                };

                AssertionResult RunPredicateFormatter(Behavior behavior) {
                    auto matcher = MakeMatcher(new MockMatcher);
                    PredicateFormatterFromMatcher<Matcher<Behavior>> predicate_formatter(
                            matcher);
                    return predicate_formatter("dummy-name", behavior);
                }
            };

            TEST_F(PredicateFormatterFromMatcherTest, ShortCircuitOnSuccess) {
                AssertionResult result = RunPredicateFormatter(kInitialSuccess);
                EXPECT_TRUE(result);  // Implicit cast to bool.
                std::string expect;
                EXPECT_EQ(expect, result.message());
            }

            TEST_F(PredicateFormatterFromMatcherTest, NoShortCircuitOnFailure) {
                AssertionResult result = RunPredicateFormatter(kAlwaysFail);
                EXPECT_FALSE(result);  // Implicit cast to bool.
                std::string expect =
                        "Value of: dummy-name\nExpected: [DescribeTo]\n"
                        "  Actual: 1, [MatchAndExplain]";
                EXPECT_EQ(expect, result.message());
            }

            TEST_F(PredicateFormatterFromMatcherTest, DetectsFlakyShortCircuit) {
                AssertionResult result = RunPredicateFormatter(kFlaky);
                EXPECT_FALSE(result);  // Implicit cast to bool.
                std::string expect =
                        "Value of: dummy-name\nExpected: [DescribeTo]\n"
                        "  The matcher failed on the initial attempt; but passed when rerun to "
                        "generate the explanation.\n"
                        "  Actual: 2, [MatchAndExplain]";
                EXPECT_EQ(expect, result.message());
            }

        }  // namespace
    }  // namespace gmock_matchers_test
}  // namespace testing

#ifdef _MSC_VER
# pragma warning(pop)
#endif
