Tests fail if python3.8 is not installed

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No description provided.

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The issue comes from this line in a fixture

check_python_has_venv("python3.8", python_test_path)

@ychiucco

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Ref #520

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This should be fixed via 3a2e47a

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After some digging, it turns out that this is hard to solve due to the twofold use of our tests (testing tasks running locally or via slurm on a docker slurm cluster).
The install_dummy_packages fixture is where the problem appears explicitly:

• Setting python_version=3.9 for tasks will lead to failures if python3.9 or its venv module are not installed.
• Setting it to None will lead to failures when running in the slurm docker, because it may point to (e.g.) python3.10 which is then not available in the slurm docker containers.

The goal (letting someone without python3.9 run the CI) is not worth the effort (splitting the fixture into two functions, one for each case), IMHO.

Won't fix.

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For the record, this is how we would add python3.11 from the Dockerfile

RUN apt-get update
RUN apt-get update
RUN apt-get install software-properties-common -y
RUN add-apt-repository ppa:deadsnakes/ppa -y
RUN apt-get update
RUN apt-get install python3.11 -y
RUN apt-get install python3-venv -y