Ideally I'd just check the `GroupTests.add_member` calls `email_user_about_group_membership_status_change` and then create a bunch of detailed tests in `test_tasks.py` directly calling `email_user_about_group_membership_status_change` and checking subject, recipient, templates used etc.

This 'd probably allow the `# Odd things happen in some of our tests. Don't worry about it.` lines to go away.