Update pytest dependencies and configuration for better compatibility.
Review Request #11995 — Created Jan. 24, 2022 and submitted
We now install the right versions of
right versions of Python.
Pytest is now configured to require the necessary plugins before it
runs, and to test explicitly the files, functions, and classes we want
it to test.
Successfully installed the right packages in a series of virtualenvs.
All unit tests pass for all supported versions of Django and Python.
Verified both with tox.