Add an assignment to a course. Verify that, on the form, you can set any of the four date-time settings to the nearest minute. Add a user override. (First enrol a student in the course if you don't already have one.) Verify that, on the form, you can set any of the three date-time settings to the nearest minute. Add a group override. (First create a group in the course in necessary.) Verify that, on the form, you can set any of the three date-time settings to the nearest minute. On the assignment main page, click "View all submission" For one student, choose Edit -> Grant extension. Verify that you can set the extension date-time to the nearest minute. Spot-check any other forms that use date selectors that you want to test. They should all use step 1 minute.