I am not a Python programmer. I don't do much work at all in Python. (It is almost entirely accurate to say that I do not use Python at all.) I haven't tried their test systems, which seem sort of OK. One is jUnit. The other sounds neater: you provide a transcript of an interactive Python session, which the test framework tries to reproduce.
I just thought it would be fun to produce TAP in Python. It's got some issues, but not many, and basically works. It's super-simple because it isn't thread safe -- and I have no interest in making it so.
I had some fun writing it, and even found a nice little bug in Test::Builder while doing it. In talking to Schwern about the bug, I learned about the refactoring Schwern and chromatic were working on, and stole those ideas. (I think I also contributed one back, so I don't feel too thiefly.)
So, my library provides TAP.Builder, which is very similar to Test::Builder. It doesn't deal with exporting at all, because that's all different in Python. I also implemented Test::More, but it sucked. To write a useful Test::More equivalent, I need to use Python more so that I understand the useful things to provide, and how to do so properly.
Writing this reminded me of two things: (1) Python isn't as annoyance-ridden as I sometimes thing and (2) Python's actual annoyances are incredibly annoying. I long for anonymous functions, useful destructors, and interpolation (not template strings). Still, I had fun.