In attempting to migrate homer's CI tests to run on our buster image, which includes Python 3.8, I've found that it's taking an awfully long time and eventually times out on the test installdeps steps; possibly the same problem as T270795: cumin's test dependencies trigger excessive pip backtracking? https://integration.wikimedia.org/ci/job/homer-tox-docker/179/console
Note however that the test also seem to not pass on the old stretch image we're moving from, erroring in the "py37-bandit" step: https://integration.wikimedia.org/ci/job/homer-tox-docker/178/console