'Create users accounts. The first three, we give helpful names
to. If there are any more, we auto-generate number IDs. We
intentionally use slightly different conventions for different
users, so we exercise more corner cases, but we could
standardize if this is more hassle than it\'s worth.'

def setUp(self):

    super(XBlockStudentTestCaseMixin, self).setUp()
    for (idx, student) in enumerate(self.student_list):
        username = 'u{}'.format(idx)
        self._enroll_user(username, student['email'], student['password'])
    self.select_student(0)
