improve pytest configuration

[pmeier]

pytest's default configuration is horrible with respect to a few aspects:

• traceback (--tb): default is "long" which not only shows a few lines above and below the one the error happened for each frame, but also the docstring for every stack. This easily buries the information I need in a lot of noise. "short" is better, but still pretty noisy. "native" is what Python gives you by default, which already includes a lot of information.
• xpass (-rX / xfail_strict = True): By default, the @pytest.mark.xfail is not strict. This means whether the test fails or not, pytest will never return a non-zero exit code. Since most people just look for a boolean signal from CI this can easily hide errors. With the xfail_strict = True setting, unexpectedly passing tests cause the run to fail.
• warnings (-Wd): pytest follows Pythons convention and adopts the same warning filters. This means for example that DeprecationWarning's are not shown. However that is very useful information for developers. Setting -Wd disables the filter and thus all warnings are shown.

This PR adapts the pytest.ini configuration file to have more sensible "defaults".

cc @kcpevey since we touched on this offline before.

[pmeier]

This is more of a QoL improvement. with this one can type pytest without specifying anything else to run these tests. LMK if you want me to revert this.

[pmeier]

I personally would go a step further

Suggested change

	# enable all warnings
	-Wd
	# turn warnings into errors
	-We

Right now there aren't any warnings so this is a good time to adopt such a change. With this option set, we get an early heads-up if something is about the change in the future.

[pmeier]

I also added the pytest.ini file the to CI workflow triggers

[kcpevey]

These look good to me. Not sure if we want one more approval on this. Maybe from @iameskild or @viniciusdc ?

[kcpevey]

This has been open for a while. I approved it and didn't hear any negative feedback so I went ahead and merged.

[costrouc]

Team agrees this is a useful commit to have warnings as errors.