def METHOD_NAME(self):
    """
    Verify that any not expected field name in the post-back is not stored
    in the database
    """
    data = dict.copy(self.student_answers)
    data['csrfmiddlewaretoken'] = 'foo'
    data['_redirect_url'] = 'bar'
    data['course_id'] = str(self.course.id)
    resp = self.client.post(
        self.postback_url,
        data
    )
    assert resp.status_code == 200
    answers = self.survey.get_answers(self.student)
    assert 'csrfmiddlewaretoken' not in answers[self.student.id]
    assert '_redirect_url' not in answers[self.student.id]
    assert 'course_id' not in answers[self.student.id]
    # however we want to make sure we persist the course_id
    answer_objs = SurveyAnswer.objects.filter(
        user=self.student,
        form=self.survey
    )
    for answer_obj in answer_objs:
        assert str(answer_obj.course_key) == data['course_id']