TST: fix compatibility pytest 8.0 - #15809

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Thanks! Failures only show up in the predeps job in daily cron, so I just kicked off the cron jobs.

Maybe I need to add remote data directive to the devinfra job below because these were obviously overlooked. Not sure why I didn't catch these in #15054 ; that PR also had cron jobs run.

Huh why is devinfra even failing here? I have restarted a previously passing build on main from 3 days ago to see if this is even related or not to this PR: https://github.com/astropy/astropy/actions/runs/7375363390

pluggy._manager.PluginValidationError: Plugin 'pytest_filter_subpackage' for hook 'pytest_ignore_collect'
hookimpl definition: pytest_ignore_collect(path, config)

UPDATE: Previously successful build now fails on rerun, so we can ignore devinfra failure in this PR.

This failure is related: https://github.com/astropy/astropy/actions/runs/7412818159/job/20170416343?pr=15809

Oh good catch. You actually reported it already but I didn't see it locally so I assumed it was gone. I can look this one first thing tomorrow but feel free to push to this branch in the mean time if it's considered urgent.

if it's considered urgent

Since pytest 8.0 is still in RC stage and not released, not super urgent. I can wait. Thanks!

I'll worry about the remaining failures later. One fire at a time. Thanks!

Note for my future self: I was thinking about adding --remote-data to devinfra to catch things like this earlier but then I realized devdeps would also pick up pre-releases, and devdeps runs a lot via CI for PRs, so maybe existing setup is enough? If someone feels otherwise, feel free to open follow-up issue or PR.

UPDATE: I think I confused myself. --remote-data isn't the problem here. predeps install all dependencies but not devdeps and not sure if we want to.