Units tests and python versions

[GernotMaier]

I was thinking a little bit more on testing different python versions and my conclusion is that in the current phase of development, we should only test the newest stable version (3.11).

Routine usage of simtools as part of DPPS will a long time ahead. It almost certain that 3.9 is outdated until then, unlikely that we use 3.10 given that 3.11 is already there now.

This might break thinks in some occasions - but without a difference: we would fix it anyway.

And version changes do not happen so often, so developers should not have an issue with updating their environment.

[VictorBarbosaMartins]

I agree that at the moment we could spare some time in the tests by dropping support to previous python versions, although reintroducing a python version later, if needed, could be a hassle. Therefore, I think it is best to closely monitor within DPPS which python versions the system as a whole wants to support. This decision, I think, should be taken aligned with the other pipelines in DPPS.

[GernotMaier]

You mean it would be a hassle if our code would work with a newer version, but not with an older? Again, given that we are years from deployment, I don't see that this is an issue right now.

[VictorBarbosaMartins]

I meant that it could be a lot of work if we have to make the code compatible with a previous python version in case there is such a demand from DPPS, for example, in the future. But if such a demand is unlikely (worth checking within DPPS), I agree to already remove the support to previous versions.

[orelgueta]

I don't have a strong opinion either way, so I would be happy with whichever decision.

[GernotMaier]

OK, then let's do this: we comment out the following points in the matrix:

          - os: ubuntu-latest
            python-version: "3.9"
            install-method: pip

          - os: macos-latest
            python-version: "3.9"
            install-method: pip

          - os: ubuntu-latest
            python-version: "3.10"
            install-method: mamba

          - os: ubuntu-latest
            python-version: "3.10"
            install-method: pip

This means we are still checking 3.9 /mamba and macos/mamba; we remove 3.10 (assuming that 3.10 is not so important for the future). Does this sound good? Would half the number of unit tests running.

[orelgueta]

Fine with me!

[GernotMaier]

Great - I am adding this now to #560 and ask for review when tests are finished.