Specifying a single testenv with platform-dependent commands

[felix-hilden]

Hi again! I'd like to propose a feature to tox.

It would be convenient to have a single testenv with platform-dependent commands. This can be done to some extent with tox already:

[testenv]
platform = win32
commands = python -c 'import sys; print(sys.platform)'

Then we can have an environment for each platform. This would be ok for running tox without any arguments, but for running tasks manually, i.e. tox -e task, this is way worse because the user needs to remember the command for their specific platform, for example tox -e task-win. In this Stack Overflow question I attempted to make a single environment that could run platform-dependent commands, but was not successful. I'll summarise it here to provide syntax that I would have expected to work. Either one should be able to define the platforms independently in all test environments:

[tox]
envlist = task

[testenv:task]
platform =
    linux: linux
    mac: darwin
    win: win32
commands =
    linux: python -c 'print("Linux")'
    mac: python -c 'print("Mac")'
    win: python -c 'print("Win")'

Or defining the platforms in the top level testenv would be fine as well:

[tox]
envlist = task

[testenv]
platform =
    linux: linux
    mac: darwin
    win: win32

[testenv:task]
commands =
    linux: python -c 'print("Linux")'
    mac: python -c 'print("Mac")'
    win: python -c 'print("Win")'

Please don't hesitate to close this issue if it's already a thing in tox 4, or if I'm simply doing something wrong. Also, I'd be fine with this being introduced in tox 4 instead of the 3.x series, because it's already on the way.

[jugmac00]

Hi @felix-hilden - you could do us a favor and test this on tox4 yourself.

Just pip install --pre tox and then use the tox4 binary instead of the tox binary.

If you rely on tox, it is a good idea anyway to test the pre-release in order to make sure your app/library will continue to work with tox after the final release.

[felix-hilden]

Thanks for the tip! I'm not sure which syntax would be the right one, but I'll give it a go later today!

[felix-hilden]

@jugmac00 There is no behavioral difference between tox 3 and 4 neither in the cases presented in the SO question nor my suggestions here. The only visual difference is that I can't see the environment skips that would happen on Linux and Mac, but that could be just obscured behind all the command line noise I see (which is likely meant to be color: ←[1m←[35mplatform-win:←[0m←[36m install_package> python -I -m pip install...)

[jugmac00]

Thank you!

If you experience problems with color rendering, please create a new issue with some minimal steps to reproduce the problem.

Other than that - the todo list for tox is long - if you feel like, do not hesitate to implement this feature on your own (for tox 4 then) - pull request welcome. But please wait until @gaborbernat has read this and says that he would accept a PR, too.