Fixed

I have this same issue. Not sure what the problem is with the test suite.

I solve this problem by not renaming main function name ("array_diff")

Eh? For me the TDD box only contains instructions on how to make my own tests. Is that really my job?

Running the example cases gives this error: This is just an example of how you can write your own TDD tests - Expected: 'expected', instead got: 'actual'

Running the actual attempt gives:

TypeError: Cannot read property 'length' of undefined
at test_array_diff
at Object.handleError
at ContextifyScript.Script.runInThisContext
at Object.exports.runInThisContext

The function I wrote works perfectly the way I tested it in my own environment.