…ubclasses

Three test classes in the certificates app were calling CourseFactory() in
setUp() despite extending SharedModuleStoreTestCase. Unlike ModuleStoreTestCase,
SharedModuleStoreTestCase shares a single modulestore across all tests in the
class and only closes MongoDB connections at tearDownClass. Calling
CourseFactory() in setUp() created a new MongoDB course (and opened connections)
for every test method without releasing them, causing connection accumulation
across the full test run.

Affected classes:
- CertificateFiltersTest (test_filters.py)
- CertificateInvalidationTest (test_models.py)
- CertificateAllowlistTest (test_models.py)

In each case the course is only read by test methods (test data such as users,
enrollments and certificates is written via Django ORM and rolled back between
tests), so sharing a single course across the class is correct.

See: https://github.com/openedx/openedx-platform/blob/master/xmodule/modulestore/tests/django_utils.py

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

When OpenEdxEventsTestMixin was listed after a TestCase subclass (e.g.
Foo(SharedModuleStoreTestCase, OpenEdxEventsTestMixin)), it landed after
unittest.case.TestCase in the MRO. Since unittest.case.TestCase.setUpClass
and tearDownClass do not call super(), the mixin's lifecycle methods never
ran. The workaround was to manually call cls.start_events_isolation() in
each class's setUpClass, but there was no corresponding tearDownClass to
restore event state, causing events disabled by one test class to leak into
subsequent classes in the same process.

Fix by placing OpenEdxEventsTestMixin first in the base class list so it
appears before unittest.case.TestCase in the MRO. This lets setUpClass and
tearDownClass run automatically through the cooperative super() chain,
removing the need for manual start_events_isolation() calls.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Pins openedx-events to the openedx/openedx-events#559 branch which
contains two fixes not yet in a released version:

- tearDownClass added to OpenEdxEventsTestMixin to restore event state
- Test utilities moved to openedx_events.testing so they are included
  in the installed package (setup.py excludes tests/ from the wheel)

Revert to unpinned once openedx/openedx-events#559 is merged and
released as 11.1.1.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

This mixin is already included via one of the other mixins on this test
class so including it again was messing with the MRO for the test
classes.