PyCharm can't find Django test

I'm running into this very same issue, but I can't find a solution for this.

Find the dummy Django project I created for this here.

This is my test configuration:

This is the project structure:

Trying to run the test results in:

AttributeError: 'super' object has no attribute 'run_tests'

Process finished with exit code 137
Empty test suite.

Obviously, running this from the shell gives no errors:

(django)mosquito@mosquito-X550LD ~/python_projects/django_test $ python manage.py test 
Creating test database for alias 'default'...
.
----------------------------------------------------------------------
Ran 1 test in 0.000s

OK
Destroying test database for alias 'default'...

Any idea what I'm doing wrong??

Thanks, Alejandro