While not required, having two browsers (ie Firefox and Chrome) or two computers will make this test easier to perform.
1. Select two users. user 1 and user 2.
2. Log in as user 1 and go to the messages page (My profile -> Messages).
3. Add user 2 as a contact if they aren't already (click on "Manage Contacts" and search for user 2).
4. From the messages page select user 2 from your contact list. The most recent messages between the two users should be displayed.
5. Click on "All messages" below the 2 user's pictures and above the message history. All messages between the two users should be displayed.
6. Click on "Recent messages". You should be returned to a listing of the last 8 messages.
7. As user 2 send user 1 nine or more messages.
8. As user 1 reload the messages page with "Recent messages" selected and verify that the list of recent messages has expanded from 8 to display all unread messages. Note that this will only happen when there are more than 8 unread messages. The "Recent messages" view should expand to show all unread messages.