CI: fix warning about "Unknown pytest.mark.pmaports_upstream_compat"
Running .gitlab-ci/run_testcases.sh -m 'not pmaports_upstream_compat'
in pmaports.git on alpine:latest shows the following warning:
/usr/lib/python3.7/site-packages/_pytest/mark/structures.py:324
/usr/lib/python3.7/site-packages/_pytest/mark/structures.py:324: PytestUnknownMarkWarning: Unknown pytest.mark.pmaports_upstream_compat - is this a typo? You can register custom marks to avoid this warning - for details, see https://docs.pytest.org/en/latest/mark.html
PytestUnknownMarkWarning,
So we are using a "custom marker" in the code to indicate, that this test case is related to upstream compatibility tests. Upstream compat tests only run when CI runs on the master branch (not in merge requests). The funny thing is, that the marker seems to work, the upstream tests do not get executed in the merge request's regular test execution. Yet pytest complains about this.
Let's try to fix this warning.
Example: https://gitlab.com/postmarketOS/pmaports/-/jobs/249897818
Related: !490 (comment 190903075)