run the tests with 'pytest' or with build_natlinkcore in the parent folderof 
natlinkcore.

don't delete confest.py or __init__.py.  These are sometimes needed by pytest.

manual_test_dragoncode.py is to be run manually froma console.
currently it reads keyboard input and can hang when called from a tool like Visual Studio Code.

Try and run in manually before a release.