Test cases shouldn't have parameters, and test files should't print anything, but I assume this file is part of the things that still need to be changed to Python style.  Anyway I think it's interesting to use gradient checking in tests; I wonder whether the test can be made small enough not to be slow.

On the other hand maybe the gradient function is small and simple enough to not need individual testing but just be tested as part of the greater thing. I don't know at this point.