`brew test python` *requires* the tcl-tk *option*

[gsteemso]

What it says. You must install an optional feature to run the Python 2.7 formula’s test method. I would submit a patch to conditionalize it, but my git install is currently broken (sorry).

Also, I have found that the tkinter module which the test tries to load may not support Python 2 any more, or something of the sort. (I'm still trying to work that part out in detail; there may be more than one potential cause of the error message I get.)

There is one positive thing – because I've got HOMEBREW_DEBUG set in my environment, which gives me an option to ignore the error, I can say that all other parts of the test routine appear to work properly.

[gsteemso]

Correction, the tkinter package loads OK. It's pip that warns of incipiently no-longer-supporting Python 2.

[sevan]

Local issue? Test only runs system bin/"pip", "list", "--format=columns" at the last phase.

[gsteemso]

Yes. Freshly installed python installs pip 20.3.4, which warns that python 2 support will be removed in pip 21.