Testing BATS locally is currently not possible

[CasperWA]

Quote from #165:

Testing it locally, the same issue will arise due to the test image used for BATS runs with Python 3.9.
So either this testing possibility should be removed, or the image should either be updated to use a newer alpine version or be completely rewritten - something that should not be too hard. One could, e.g., base it on the BATS GitHub action composite action that expects a Linux environment and then goes to town.

Talking about issue #164.

This should be addressed.