Test on multiple browsers both collapsed and expanded (for regression tests) and test on a mobile if possible Test in RTL as well as just LTR (e.g. hebrew language) You need to make sure no interface elements overlap, and the interface is useable on mobile or small screens. Login as a user Enrol yourself in a course if not already Enrol 20 people in that course so that the messaging page will have page numbers Go to messages Search for some users Search for some messages Do an advanced search Don't worry if the search box is out of screen. Just make sure it's not overlapping anything, and you can use it correctly if you scroll right Add a few students as contacts Select one, make sure the page still looks good Select a course using the dropdown menu, make sure the page still looks fine Select a participant, send them a message View conversations with your contacts Send a message Do anything else in the messaging interface that may have been missed