For some reason the bump to pytest==8.0.0 (#17675) appears to impact test discovery.
This is visible when running with truly pinned oldest test dependencies (#16963), and a periodic reminder that this PR serves a purpose and should be merged sooner rather than later to avoid discovering these issues after the fact (this should have been caught in #17655

example logs
What seems to be happening is that doctests from astropy/extern/configobj/validate.py are not compatible with pytest (they seem to be written with only python -m doctest in mind), which is normally not an issue since this module is somehow excluded from test discovery, but in that specific env (exactly our minimal dependencies), this isn't true, which leads to failing the run.

Further bumping pytest to a bugfix release might remedy this, but it's also possible that something else in our minimal set of test dependencies affects discovery (tox, coverage ?) is just not compatible with pytest 8.0 and might need a bump too. I'll run some experiments on my fork to see how best to address this.