We should have a dependency of the rec tests on the respective sim test?

good idea

urgh I did not get the warnings about pytest.mark.dependency() not being available on my machine and was hoping that we had it in the key4hep pytest install but looks like this is not the case :/ Then we will have to switch to some other test system if we want to have tests depend on each other I guess?
Any suggestions?

I think using cmake/ctest would be fine.

is there any way to set that up without requiring the for this project useless cmake/make step?

What do you mean with useless cmake step? You create a CMakeLists.txt file and run cmake and then ctest?