Hej, thanks for your work on this!

Your test application doubles some part from the examples/subfolders application, I think it would make sense to combine both into a single test application? I would now rather put it in tests/build_system as you did instead of examples. In any case, the test application needs a README explaining its purpose and structure.

Would you mind combining them into one? Also, it might be nice to find a suitable point in the documentation to add information to about the SRC variable, maybe in https://doc.riot-os.org/creating-an-application.html or https://doc.riot-os.org/build-system-basics.html.

Thanks for your feedback !

I saw the feedback of maribu (RIOT-OS#20024 (comment)) so I've removed all duplicates between test and example and added doc in create-an-application.md

Thanks, I'm gonna merge this into my branch and then rework it a bit. I think the documentation part could be shorter by simply referring to the example's README.