Refactor test routine

[FabianHofmann]

Checklist

• [x] I am using the current main branch or the latest release. Please indicate.
• [x] I am running on an up-to-date pypsa-earth environment. Update via conda env update -f envs/environment.yaml.

Problem Statement

Currently the test routine uses nested snakemake calls where snakemake is called via a bash command in the Snakefile. This architecture omits error streams and snakemake runs that fail are not reported as such, see https://github.com/pypsa-meets-earth/pypsa-earth/actions/runs/9667460555/job/26669336528#step:9:1739.

Suggestion

I would propose to execute snakemake in the GH workflow and optionally keep the commands in a common file for easy local execution, like https://github.com/PyPSA/pypsa-eur/blob/master/test.sh

I would as well propose to collect all workflow CI's in one yaml that uses a matrix entry for setting the operation systems.

[davide-f]

Wow!

That is a quite big bug! Thanks for reporting. Indeed this shouldn't be difficult as that was our previous configuration