Ability for AND combination of factors on command line.

[icemac]

What's the problem this feature will solve?

I want to select multiple factors and combined.
Using tox 3 and tox-facor together I was able to have environments like this:
py{37,38,39}-{wsgi,plonetesting,grok}-{chrome,ff,edge}
And use tox -f py37-ff to run the following environments:

• py37-wsgi-ff
• py37-plonetesting-ff
• py37-grok-ff

Using tox >= 4 and the integrated factor selector I seem to have to call:
tox -f py37 -f ff but this combines the factors with or, so it runs all combinations.

Describe the solution you'd like

I need a way to configure (multiple) -f switches to do an and combination of the selected factors.

Alternative Solutions

Currently I see no other solution than keeping to use tox < 4 together with fox-factor.

[gaborbernat]

A PR is welcome 👍

[q0w]

It could be closed because of this fix #2786?