The test cases are a mess!
there's a test on a string " xoxoox " which obviously has a space at it's end so no matter how much the 'x' and 'o' changes the space will not be effected. Eventually the result should be true but the test expects it to be false!
This challenge has another issue which is the name of the argument! it should be something else than 'map' because it can get confusing in some cases.