1. Login as teacher and navigate to course.
2. Edit existing assignment (myassign) and in "Tags" section (last section on the page), add one or more tags.
3. Press "Save and return to course".
4. Go back to "myassign" setting page, and make sure all Tags are available.
5. Delete one of the Tags and add a new one.
6. Press "Save and return to course".
7. Go back to "myassign" setting page, and make sure all Tags are available.
8. Backup the "myassign"
9. Restore it into a new Course (also a different Moodle system), and make sure the tags are available.
10. Go to Site administration ► Appearance ► Manage tags ► Default collection
11. Ensure you can see all tags.
12. Delete "myassign" assignment and go to Site administration ► Appearance ► Manage tags ► Default collection
13. Run cron
14. Ensure all tags related to myassign are deleted.

NOTE:

1. Test above instructions with a resource "Book"