pytest._pathlib.import_path should pass absolute paths on Python>=3.8 <3.10

[graingert]

In https://bugs.python.org/issue44070, spec_from_file_location() has changed its behaviour so that the responsibility of passing absolute paths is on the caller between 3.8 and 3.10

So something like this is needed:

    if (3, 8) <= sys.version_info[:2] < (3, 10) and not os.path.isabs(fn):
        # module.__spec__.__file__ is supposed to be absolute in py3.8+
        # importlib.util.spec_from_file_location does this automatically from
        # 3.10+
        # This was backported to 3.8 and 3.9, but then reverted in 3.8.11 and
        # 3.9.6
        # See https://twistedmatrix.com/trac/ticket/10230
        # and https://bugs.python.org/issue44070
        fn = os.path.join(os.getcwd(), fn)

pytest/src/_pytest/pathlib.py

Line 500 in d200598

spec = importlib.util.spec_from_file_location(module_name, str(path))

[sgaist]

Hi,

I would like to take care of this one for Hacktoberfest.

[nicoddemus]

In the end we verified this is not needed, see: #9140 (comment)

Thanks @graingert!