def test_coupon_code_not_redeemable(self):
        self.login()

        params = {'coupon_code': 'foo'}
        response = self.client.post(url_for('billing.coupon_code'),
                                    data=params, follow_redirects=True)

        data = json.loads(response.data)

        assert response.status_code == 404
        assert data['error'] == _('Discount code not found.')
State change involves other components as well.
dataset/ETHPy150Open nickjj/build-a-saas-app-with-flask/catwatch/tests/billing/test_views.py/TestBilling.test_coupon_code_not_redeemable--crossover with--dataset/ETHPy150Open circuits/circuits/tests/core/test_complete.py/Nested1.test