In a given course, enrol few students and two teachers. Change course settings to Separate groups and Force group mode . Remove the accessallgroups capability from teacher role. Create 2 groups, add few students and a teacher into each group. Add a grade item. Log in as teacher 1 and go to Grades > Single view. Make sure you only see the students that belongs to your group. Suspend the enrolment of a user. (As admin) Make sure you're not able to see this user on the single view report. Activate the student enrolment again. Make sure you are able to see this student on singleview report. Try to manupulate the URL, changing params (itemid or groupid) Make sure it will throw an error on case of invalid user id or it will not display the user of a group you dont belong. Run unit tests on : grade/report/singleview/tests/screen_test.php and make sure it pass.