I also had a look. Overall this looks great to me. I do have a few suggested changes:
Change "self.assertRaises" to "with self.assertRaises", at least in most cases (if a single function with no args is being called it may not enhance clarity enough to be worth changing, but in all other instances it enhances clarity):
I also found a few flake8 warnings about variables not being set:
- testMeasureApCorr line 139-ish apFluxName =... that line can be deleted
- testPsfIO.py line 137-ish psf = ... get rid of psf
One instance of commented-out code should probably be deleted:
- testPsfIO.py: line399-ish # def assertClose...
I actually made these changes already, but the branch got changed remotely while I did it. Not sure whether to pull and rebase or just let somebody else redo my work.