The pip PR has been in review long enough that I've started noticing more problems with it. Hopefully, I can get those taken care of eventually, probably with help.
Okay, several test iterations later, I've determined that the code was doing what it should, and my initial test was wrong. So, there's no more work to be done around the missing test coverage, because now it's not missing, and it passes.
Anyway, that's enough messing with pip for tonight.
In the future, I'm going to have to work out a better way to structure my time, because I feel like I could have done more, but for now, the best thing to do, is sleep.