You will need two browsers. Log in as two separate users (recipient and sender). Check recipient's messaging preferences and make sure that they are set to receive popups for personal messages both online and offline. 1) CHECK POPUP WORKS As sender send recipient a message. As recipient go to any course page and check that you get a message popup. Go read the message. Wait at least two minutes before continuing. 2) CHECK BLOCKING WORKS As recipient go to the messaging page and search for sender. leave the search results page open. As sender, send recipient a message. As recipient click the block link next to sender's name. Still as recipient go to a course and check that you don't get a message popup. Wait at least two minutes before continuing. 3) CHECK POPUPS WORK WITH MULTIPLE MESSAGES Unblock sender. As sender, send recipient a few more messages. As recipient, check that you now get a popup that tells you how many unread messages you have.