jhoffner already fixed this.

My code does the job. I haven't imported string. I wrote the code in less than one minute. I then spent time wondering why its wrong, another minute realising that I've wrote "UVWYXYZ" while it should be "UVWXYZ". I'll now add "import string" and I bet with my soul that it will work. I submitted, passed the test cases, but still was blocked because of an error which comes not from my implementation, but from badly written test cases and unspecified assumptions.

Also, I am absolutely outraged by the idea of defining the solution approach as illegal (not because the specification makes it impossible to finish with encode, but because somebody said so).

The actual difficulty of this Kata should be kyu7. Its harder because its broken.

Edit: I'm keeping my soul.

@zyocum To prevent cheating, I've moved the long test solution to the test cases area from the pre-loaded section so that the solution is no longer exposed. The kata still accesses it to validate solutions, but this way users can't cheat.

EDIT: I've added random tests to further prevent cheating.

I hadn't realized that. I put the tests and solutions data into the example test case section, so now it should be OK, I think. Exposing the data like that seems like it's not ideal (I would prefer a way to load test/solution data for testing purposes without exposing it to users, but apparently there's no way to do that.)

Added, thanks!

Please check again, I updated my test cases