As a teacher, open a course Navigate to Settings -> Course administration -> Users -> Groups Create three groups Select two of the groups you just created Click the 'Delete selected groups' button Click yes on the confirmation page Confirm that the groups have been removed Select the third group you created Click the 'Delete selected groups' button Click yes on the confirmation page Confirm that this group has also been removed Try visiting /groups/group.php?courseid=1&delete=1 Confirm that a debugging message is shown if developer mode is enabled Confirm that the redirect works