Fix tests on Python 3.11 (fix #18)

[musicinmybrain]

random.sample() population must be a sequence

[felixonmars]

I guess list() here should be enough as we don't need a sorted sequence?

[musicinmybrain]

I guess list() here should be enough as we don't need a sorted sequence?

Yeah, that should be fine, since we don’t care about the actual order of the set or require a reproducible pseudorandom sample for this test. It doesn’t matter much, since the sort doesn’t have a significant cost in test runtime, but I’ll force-push with your suggested change.