This tests array.splice behavior. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS arr is ['a','b','c','d'] PASS arr.splice(2) is ['c','d'] PASS arr is ['a','b'] PASS arr.splice(0) is ['a','b'] PASS arr is [] PASS arr.splice() is [] PASS arr is ['a','b','c','d'] PASS arr.splice(undefined) is ['a','b','c','d'] PASS arr is [] PASS arr.splice(null) is ['a','b','c','d'] PASS arr is [] PASS arr.splice(100) is [] PASS arr is ['a','b','c','d'] PASS arr.splice(-1) is ['d'] PASS arr is ['a','b','c'] PASS arr.splice(2, undefined) is [] PASS arr.splice(2, null) is [] PASS arr.splice(2, -1) is [] PASS arr is ['a','b','c'] PASS arr.splice(2, 100) is ['c'] PASS arr is ['a','b'] PASS successfullyParsed is true TEST COMPLETE