[Python-modules-team] Bug#914420: Bug#914420: python-pytest: Breaks many Python 2 test suites

[Ole Streicher]

Hi Ondrey,

newer astropy (>= 3.x) is limited to Python 3.x, and the problem appears
only with Python 2.7. The "python-astropy" package mentioned in the
Affects field of the bug is the stable (but supported) version 2.0.x,
which is (now) Python-2 only. The other packages mentioned there support
both Python branches, and there only Python 2 is affected.

By reading the upstream changelog, I could not find a cause what should
cause the incompatibility. Also, the logs now all contain a warning like

/usr/lib/python2.7/dist-packages/_pytest/cacheprovider.py:58
  /usr/lib/python2.7/dist-packages/_pytest/cacheprovider.py:58:
PytestWarning: could not create cache path
/usr/lib/python2.7/dist-packages/aplpy/.pytest_cache/v/cache/nodeids
    PytestWarning(fmt.format(**args) if args else fmt), self._config

which is not present in the Python 3 runs (and also not with pytest
3.6.4) -- this shows that probably something goes wrong when using
pytest/Python2 on installed packages.

For python-m3u8, the CI test is a simple m3u8.loads() call that does not
invoke pytest at all.

Best

Ole