NOTE: This test requires a course with a teacher and several students enrolled.
(1) As the teacher, create a group and add all but one student to the group.
(2) Create an assignment (online text for speed) and in Group submission settings select the following: Students submit in groups=Yes and Require group to make submission=Yes and separate groups.
(3) Log in as a student in the group and verify you can add a submission
(4) Log in as the one student who is NOT in the group and verify you get the message: "You're not a member of any group;please contact your teacher".