0.8.1 incompatible with pytest-qt + pytest-cov on travis

[Sheeo]

When both pytest-qt and pytest-cov are installed, none of the py test plugins are picked up by py.test --fixtures .

Only happens if all three plugins are loaded. Unclear if this is pytest-mock's fault, pytest-cov, pytest-qt or py.test's fault.

Minimally failing travis build here: https://travis-ci.org/FAForever/server/builds/88285397

Log output:

    $ python --version
    Python 3.5.0
    $ pip --version
    pip 7.1.2 from /home/travis/virtualenv/python3.5.0/lib/python3.5/site-packages (python 3.5)
    install
    4.04s$ pip install --use-wheel pytest-mock pytest-qt pytest-cov
    Collecting pytest-mock
      Downloading pytest_mock-0.8.1-py2.py3-none-any.whl
    Collecting pytest-qt
      Downloading pytest_qt-1.8.0-py2.py3-none-any.whl
    Collecting pytest-cov
      Downloading pytest_cov-2.2.0-py2.py3-none-any.whl
    Requirement already satisfied (use --upgrade to upgrade): pytest>=2.4 in /home/travis/virtualenv/python3.5.0/lib/python3.5/site-packages (from pytest-mock)
    Collecting coverage>=3.7.1 (from pytest-cov)
      Downloading coverage-4.0.1.tar.gz (349kB)
        100% |████████████████████████████████| 352kB 756kB/s
    Requirement already satisfied (use --upgrade to upgrade): py>=1.4.29 in /home/travis/virtualenv/python3.5.0/lib/python3.5/site-packages (from pytest>=2.4->pytest-mock)
    Building wheels for collected packages: coverage
      Running setup.py bdist_wheel for coverage
      Stored in directory: /home/travis/.cache/pip/wheels/3d/2d/5f/5e812a155cc0752a0f99157ee14aebbcd87b8d425083f463f5
    Successfully built coverage
    Installing collected packages: pytest-mock, pytest-qt, coverage, pytest-cov
    Successfully installed coverage-4.0.1 pytest-cov-2.2.0 pytest-mock-0.8.1 pytest-qt-1.8.0
    0.55s$ py.test --fixtures . | grep mock
    The command "py.test --fixtures . | grep mock" exited with 1.
    Done. Your build exited with 1.

Confirmed working with pytest-mock==0.7

[Sheeo]

Cancel that, https://travis-ci.org/FAForever/server/builds/88285865 failed and I have no clue why at this point.

[The-Compiler]

If you pass -rw to show the pytest warnings, you'll likely get something like this:

================= pytest-warning summary =================
WI2 None could not load setuptools entry import: pytest-qt requires either PySide, PyQt4 or PyQt5 to be installed

Gladly @nicoddemus is pytest-qt, pytest-mock and pytest maintainer/contributor, so I guess we can still discuss this here 😉

Some things come to mind:

• Warnings like this one (as compared to deprecation warnings) really should be shown by default, and probably be fatal.
• pluggy might need some way to handle ImportError for each plugin individually and still load other plugins rather than aborting - /cc @hpk42
• Maybe pytest-qt should raise something other than ImportError? But I guess it's still the most appropriate thing...

[Sheeo]

Thanks! Indeed what recently happened in the project was a removal of PySide dependency, but pytest-qt was mistakenly left in as a dependency.

I concur with your thoughts.

[nicoddemus]

Maybe pytest-qt should raise something other than ImportError?

Arguably raising RuntimeError would be appropriate too and would alleviate the problem. What do you guys think?

[The-Compiler]

Yeah, why not - how does this look to the user? Will it be shown as an INTERNALERROR> or as something more sensible?

[nicoddemus]

Instead of a hidden pytest-warning, it breaks with a full blown exception:

λ py.test foo.py -rw
Traceback (most recent call last):
  File "E:\Miniconda\envs\test-pytesqt\Scripts\py.test-script.py", line 5, in <module>
    sys.exit(main())
  ...
  File "E:\Miniconda\envs\test-pytesqt\lib\site-packages\pytestqt\logging.py", line 7, in <module>
    from pytestqt.qt_compat import qInstallMsgHandler, qInstallMessageHandler, \
  File "E:\Miniconda\envs\test-pytesqt\lib\site-packages\pytestqt\qt_compat.py", line 49, in <module>
    QT_API = _guess_qt_api()
  File "E:\Miniconda\envs\test-pytesqt\lib\site-packages\pytestqt\qt_compat.py", line 36, in _guess_qt_api
    raise RuntimeError(msg)
RuntimeError: pytest-qt requires either PySide, PyQt4 or PyQt5 to be installed

I think this is better than silently hiding it.

IIRC that was the behavior pre-pluggy too.

[The-Compiler]

Yeah, why not, let's do that.

[nicoddemus]

OK, created an issue for it in pytest-qt: pytest-dev/pytest-qt#109

[nicoddemus]

Thanks @Sheeo for bringing this up. 😄

[Sheeo]

You're welcome @nicoddemus, keep up the good work 👍