Test suite fails to run if any requests are first processed by BE

[ssciolla]

After using docker-compose up to load the application in development mode, if any requests are processed by the backend, the test suite (i.e. python manage.py test -v 3) seems to fail to run within the student_explorer container.

django.db.utils.OperationalError: Problem installing fixture '/usr/src/app/student_explorer/fixtures/dev_users.json': Could not load auth.User(pk=1): (1205, 'Lock wait timeout exceeded; try restarting transaction')

Note that it should work if you simply run docker-compose up and immediately run the test suite within the container.

Theoretically, according to Django's "Writing and running tests" docs, a separate test database should be created and destroyed on each run. There seems to be some issue loading dev_users.json when this 'request then test' situation occurs.