Remove pytest-runner setuptools integration

[abravalheri]

Recently pytest-dev/pytest#5546 was merged with a discussion about not recommending pytest-runner integration with setuptools.

Does this affect PyScaffold in any sense?

[FlorianWilhelm]

@abravalheri, good point. Personally, I don't use python setup.py test at all anymore but run py.test or tox directly. If this is now recommended I would also be in favour of just dropping the runner. Would doctest still work? Would we lose anything else? We should then also remove it from the documentation.

[abravalheri]

I am under the impression that we would need to create a explicit tox testenv for doctest.
Something like this: https://ofosos.org/2019/01/06/doctest-travis/

I think that is the main drawback, isn't it? I don't think we have anything extra to loose...

[FlorianWilhelm]

Agreed. Judging from the source code of ptr, it's not responsible for the doctest command of setup.py but it's coming from Sphinx. So we could just remove ptr and state it in the Changelog.rst as well that we dropped it. A unit test that doctest still works would be nice but not really necessary since Sphinx registers this and we are in no way messing with this.

[jayvdb]

setuptools has also deprecated test. pypa/setuptools#1684

[FlorianWilhelm]

Okay, then the decision is made. Let's remove it in version 4.0 from the docs and als the py.test runner contrib package. I am quite happy with this since it will reduce the code and complexity. I haven't used python setup.py test for ages and always call py.test directly.

Any volunteers to provide a PR for the v4.0.x branch?