public void Orders_CreateEinvoiceOrder()
        {
            // Arrange
            var url     = ConfigurationManager.AppSettings["MultiSafepayAPI"];
            var apiKey  = ConfigurationManager.AppSettings["MultiSafepayAPIKey"];
            var client  = new MultiSafepayClient(apiKey, url);
            var orderId = Guid.NewGuid().ToString();

            var orderRequest = OrderRequest.CreateDirectEinvoiceOrder(orderId, "product description", 12100, "EUR",
                                                                      new PaymentOptions("http://example.com/notify", "http://example.com/success", "http://example.com/failed"),
                                                                      GatewayInfo.PayAfterDelivery(new DateTime(1986, 08, 31), "NL39 RABO 0300 0652 64", "+31 (0)20 8500 500", "*****@*****.**", "referrer", "useragent"),
                                                                      new ShoppingCart
            {
                Items = new[]
                {
                    new ShoppingCartItem("Test Product", 100.0, 1, "EUR")
                }
            },
                                                                      new CheckoutOptions()
            {
                TaxTables = new TaxTables()
                {
                    DefaultTaxTable = new TaxTable()
                    {
                        Name  = "Default",
                        Rules = new[] { new TaxRateRule()
                                        {
                                            Rate = 0.21
                                        } },
                        ShippingTaxed = false
                    }
                }
            },
                                                                      new Customer()
            {
                FirstName   = "Testperson-nl",
                LastName    = "Approved",
                HouseNumber = "1/XI",
                Address1    = "Neherkade",
                City        = "Gravenhage",
                Country     = "NL",
                PostCode    = "2521VA",
            },
                                                                      new DeliveryAddress()
            {
                FirstName   = "Testperson-nl",
                LastName    = "Approved",
                HouseNumber = "1/XI",
                Address1    = "Neherkade",
                City        = "Gravenhage",
                Country     = "NL",
                PostCode    = "2521VA",
            }
                                                                      );

            // Act
            var result = client.CreateOrder(orderRequest);

            // Assert
            Assert.IsNotNull(result);
            Assert.AreEqual(orderRequest.OrderId, result.OrderId);
            Assert.IsTrue(result.PaymentUrl.StartsWith("http://example.com/success?transactionid=")); // redirect to success URL
        }