Run behat suite for @mod_forum Create a visibly grouped forum in a course without groups, and another forum without any group settings Post a message to each group in the first forum, and another post to "All participants" Reply to each message Move each of the discussions from the first forum into the second forum Edit the first post in each discussion Confirm that you can select the group when editing Confirm that you can only see the 'All participants' group Change the group to 'All participants' Edit the reply in each discussion Confirm that you cannot select the group when editing Move each of the discussion back to the first forum Edit the first post in each discussion Confirm that you can select the group when editing Confirm that you can see all of the groups again Change the group in each post back (one discussion per group) Edit the reply in each discussion Confirm that you cannot select the group when editing You may also like to look how posting to groups in all three activity group modes works with: no groups student in one group student in multiple groups tutor in one group tutor in multiple groups Note: the behat tests cover all of the above.