# Example 4 - order validation shouldn't depend on ordering of items
def test_4(self):
    num_items = 12
    items = [c.Item(type='product', description='tv', amount=99999, quantity=num_items)]
    for i in range(num_items):
        items.append(c.Item(type='payment', description='invoice_' + str(i), amount=99999, quantity=1))
    order_1 = c.Order(id='1', items=items)
    self.assertEqual(c.validorder(order_1), 'Total amount exceeded')

    # Put payments before products
    items = items[1:] + [items[0]]
    order_2 = c.Order(id='2', items=items)
    self.assertEqual(c.validorder(order_2), 'Total amount exceeded')