allow running tests locally with pytest -m "not mqtt", to deselect the mqtt cases.
Fixes an issue where recurrent jobs were executed twice at the end which should not happen generally.
fix pytest warnings in scheduling and SampleRole
classes with Test as prefix create pytest assumptions
periodic jobs in scheduling were not cancelled correctly
allow running tests locally with
pytest -m "not mqtt", to deselect the mqtt cases. Fixes an issue where recurrent jobs were executed twice at the end which should not happen generally.