pytest command should use pyargs instead of path based option

[ianmkenney]

For compiled projects, path-based pytests will fail. See the failed tests with mdaencore.

https://github.com/MDAnalysis/mdaencore/actions/runs/5648200654/job/15300027899#step:8:34

This is because the *.so files are not found. Using pyargs ensures that the proper package is imported.

pytest -n 2 -v --cov=mdaencore --cov-report=xml --color=yes --pyargs <PACKAGENAME>

Side note: should we replace -n 2 with -n auto?

[IAlibay]

I'm not sure why the *.so files wouldn't be found. using --pyargs has a lot of disadvantages (including not being able to use local extensions properly). I wouldn't advocate for it in nearly all cases.

[IAlibay]

should we replace -n 2 with -n auto?

I would second this.

[IAlibay]

I'm not sure why the *.so files wouldn't be found. using --pyargs has a lot of disadvantages (including not being able to use local extensions properly). I wouldn't advocate for it in nearly all cases.

To clarify here - plenty of projects don't use pyargs and have .so files. I think there's a deeper issue here that's being overlooked.