Spent the bulk of the day testing handling of fairly rare occurences. Found a number of bugs in the new code, no big deal there. Then discovered that the same code in the original code suffers from almost the same problem. Okay, annoying. But now that I've fixed it I seem to be running into a bug in the test framework that's never shown up before.

Think I've just been staring at it too long today. Going to leave it and work on it again tomorrow. Maybe I'll wake up and it will have fixed itself.