'Ensure a non-existent course results in a 404.'

def test_nonexistent_course(self):

    self.user = self.create_user_for_course(self.course, CourseUserType.ANONYMOUS)
    url = course_home_url_from_string('not/a/course')
    response = self.client.get(url)
    self.assertEqual(response.status_code, 404)
