Please clarifiy in documentation whats running/specified for python development versions

[tyll]

Travis supports development version like 3.8-dev but it is unclear if a config like

[travis]
python =
  3.8: py38,coveralls,custom

should run all envs for the Travis python 3.8-dev job or not. It seems that it runs only py38 and not the others, maybe due to some default selection.

This came up here: https://github.com/linux-system-roles/template/pull/23

[ryanhiebert]

This is expected behavior. Declared configuration is always matched exactly, so having "3.8-dev" in the Travis configuration won't match "3.8" in the tox-travis config. Instead, it falls back to the default behavior, which is to auto-discover what version of Python is running, and run the pyXX env for that version of Python.

You might argue that it would be better to have it default to using the same thing as the "3.8", but I think that would be confusing. We want to make sure that it is straightforward to provide a different configuration between 3.8 and 3.8-dev, and we certainly wouldn't expect anything but strict matching for different, non-python factors, IMO.

I'd recommend making a line for 3.8-dev just like you have made for all the other versions.

If you think a documentation enhancement is warranted, I'd be happy to review a pull request.

[tyll]

Ok, thank you. I will prepare something. What is not clear for me is that "3.8" does not refer to the python version of the python executable but the version of the Travis environment.