I have a similar issue when trying this in Python. All tests are passed, but exits with code 1, saying that I'm passing an empty argument to the max() function. In fact, it is a list with all the difference values. This is also surprising for me since indeed many people passed this kata.

UPDATE: Just after writing the above, I went back to my solution and realised I didn't account for the case if one of the lists is empty, as the kata asks. That solved my issue. Please check if your solution fulfills all requirements and not just looks for the maximum difference in string lengths.

467 guys passed the Ruby translation so I am sure there are no errors. I am sorry but issues are for problems in the kata, not for problems in your code.