'Tests that calling add_users multiple times before a single call
to remove_users does not result in the user remaining in the group.'

def test_add_users_doesnt_add_duplicate_entry(self):

    role = CourseStaffRole(self.course_key)
    role.add_users(self.student)
    self.assertTrue(role.has_user(self.student))
    role.add_users(self.student)
    role.remove_users(self.student)
    self.assertFalse(role.has_user(self.student))
