Avoid `__init__.py` in tests directory

[HolgerPeters]

The pytest docs (https://pytest.org/latest/goodpractises.html) advice to not put an __init__.py file into the tests directory:

avoid “init.py” files in your test directories. This way your tests can run easily against an installed version of mypkg, independently from the installed package if it contains the tests or not.

[FlorianWilhelm]

@HolgerPeters Good point, thanks, are you up for a PR?

[HolgerPeters]

yes I am, probably not this week though.

[HolgerPeters]

I suggest replacing __init__.py by a conftest.py (https://pytest.org/latest/plugins.html) if the directory tests would be empty, it would not persist in git - and adding a conftest.py seems better than checking in a .dummy.txt

[FlorianWilhelm]

Yes, sounds like a good plan.

[FlorianWilhelm]

@HolgerPeters Your PR was merged and a dummy conftest.py file is created with a bit of information about it.