Unit tests for logging in Schedule.create_assignment() fail when running tests from base directory

[monoclecat]

Unit tests in test_model_Schedule.py work fine when run one at a time but fail when running unit tests from the base test directory.

python3 manage.py test webinterface.tests.unit_tests fails
but
python3 manage.py test webinterface.tests.unit_tests.test_model_Schedule runs well.