1. Login as a teacher and create a forum with 'Force everyone to be subscribed' set to No.
2. Login as a student and check that you can choose to subscribe/unsubscribe.
3. Login as a teacher and create a forum with 'Force everyone to be subscribed' set to 'Yes, forever'.
4. Login as a student and check that you are subscribed with no option to unsubscribe.
5. Login as a teacher and create a forum with 'Force everyone to be subscribed' set to 'Yes, initially'.
6. Login as a student and check that you are subscribed initially but have the option to unsubscribe.
7. Login as a teacher and create a forum with 'Force everyone to be subscribed' set to 'Subscriptions not allowed'.
8. Login as a student and check that you have no option to subscribe.