Tests side-effect-free evaluation

Running test: basicTest
Paused on "debugger;"
f() returns 1
g() returns 2
f() returns 1
g() throws EvalError

Running test: testDate
someGlobalDate.setDate(10) : throws
new Date().setDate(10) : ok
someGlobalDate.setFullYear(1991) : throws
new Date().setFullYear(1991) : ok
someGlobalDate.setHours(0) : throws
new Date().setHours(0) : ok
someGlobalDate.getDate() : ok
new Date().getDate() : ok
someGlobalDate.getFullYear() : ok
new Date().getFullYear() : ok
someGlobalDate.getHours() : ok
new Date().getHours() : ok
