Replace use of deprecated 'setup.py test' with pytest

[jdufresne]

Since setuptools v41.5.0 (27 Oct 2019), the 'test' command is formally
deprecated and should not be used. Now, run the pytest command directly
as recommended by setuptools.

[jdufresne]

The pytest runner project also lists itself as deprecated: https://github.com/pytest-dev/pytest-runner

[liZe]

Thanks a lot for your pull requests, and sorry for being so long.

As explained in Kozea/cairocffi#147, I’m currently working on new packaging tools and I’m trying to fix a lot of things related to the package structure. You can check the flit branch, I’m using tinycss2 as a packaging laboratory 😄. My goal is to have a very, very simple setup, with the smallest number of files in the root of the repository, and simple commands to package, test and release the module.

[jdufresne]

But I didn’t find a clean solution yet to launch tests out of the box.

If you'd like, I could add a tox.ini to the project. tox is commonly used by other Python projects and is the de facto standard as a Python test entry point. It is also recommended by setuptools.

See https://tox.readthedocs.io/en/latest/

[liZe]

If you'd like, I could add a tox.ini to the project.

Well… I don’t know. I’ve had bad experiences with tox in the past, and I’d like to avoid external tools when possible. I’m happy with Travis, and even if tox has a lot of features, I’m not sure that they are really useful for tinycss2.

I’ll try to build my "perfect" packaging setup, check your pull requests to see if they match what I’ve done, and I’ll be happy to discuss my choices in this PR.

[liZe]

@jdufresne If you’re interested, you can try the flit branch. Thanks again for your pull requests, they’re really close to what I wanted to do.

Packaging with flit is really close to my packaging dreams. Both the source and the wheel packages are what I’ve always wanted to get: documentation, tests and extra files are included in the source, and the wheel contains only code.

🍾🍾🍾

Of course, I’m a bit afraid to find installation problems for some users after the release…

Documentation has also been updated. I have 2 pages left to write, but it’s much better this way.