Pytest configuration needs review

[heplesser]

When running make installcheck on NEST on my computer (and some others), pytest issues warnings about PytestUnknownMarkWarning:Unknown pytest.mark.skipif_missing_threads - is this a typo? even though this marker is defined in

nest-simulator/testsuite/pytests/conftest.py

Lines 82 to 89 in c201d67

	@pytest.fixture(autouse=True)
	def skipif_missing_threads(request, have_threads):
	"""
	Globally applied fixture that skips tests marked to be skipped when
	multithreading support is missing.
	"""
	if not have_threads and request.node.get_closest_marker("skipif_missing_threads"):
	pytest.skip("skipped because missing multithreading support.")

.

I can also reproduce this warning by running a test directly from its install location, e.g.

pytest bld/main/mpi/install/share/nest/testsuite/pytests/sli2py_other/test_multithreading.py    

If, on the other hand, I run the same test from the source code directory

pytest src/main/testsuite/pytests/sli2py_other/test_multithreading.py    

I do not get the warning. I confirmed with diff that the two testsuite directories are identical except for entirely unrelated files such as README.md.

The interesting difference is that the source directory contains pyproject.toml at the top level, which provides som pytest initialiasation:

nest-simulator/pyproject.toml

Lines 1 to 8 in c201d67

	[tool.pytest.ini_options]
	markers = [
	"skipif_missing_gsl: skip test if NEST was built without GSL support",
	"skipif_missing_hdf5: skip test if NEST was built without HDF5 support",
	"skipif_missing_mpi: skip test if NEST was built without MPI support",
	"skipif_missing_threads: skip test if NEST was built without multithreading support",
	"simulation: the simulation class to use. Always pass a 2nd dummy argument"
	]

Indeed, copying pyproject.toml into the installed testsuite directory makes the warning disappear.

It seems wrong to my to install pyproject.toml into the installed testsuite directory just to avoid this warning. I also noticed that conftest.py contains code to insert one marker into the configuration:

nest-simulator/testsuite/pytests/conftest.py

Lines 54 to 59 in c201d67

	See https://docs.pytest.org/en/8.0.x/how-to/mark.html.
	"""
	config.addinivalue_line(
	"markers",
	"requires_many_cores: mark tests as needing many cores (deselect with '-m \"not requires_many_cores\"')",
	)

So I wonder if the material in the toml file should be moved to conftest.py or if one should find some other solution?

Test execution and skipping appears to work in spite of the warning, so I labeled this maintenance, not a bug.