CLONE - A teacher can use a single-item scale for rating

This test requires a forum containing several posts.

1. Login as a teacher and create a single-item scale in the course e.g. 'Like'.
2. Update the forum and enable the single-item scale, setting the aggregate type to 'Average of ratings'.
3. Rate some posts in the forum.
4. After rating a post, click on the rating link and check that the popup window correctly displays the name of the user who rated the post, the rating and the time.
5. Check that it is possible to remove a rating.
6. Go to the gradebook and check that the ratings are listed correctly.
7. Check that the single-item scale cannot be deleted from the Scales page, as it is in use.
8. Update the forum and set the aggregate type to 'No rating'.
9. Check that the single-item scale can now be deleted.