public void OrderUpdateMerchantReference()
        {
            // TODO uncomment below to test the method and replace null with proper value
            string id = null;

            var authorization       = authorizationApi.AuthorizationCreateToken("https://auth-dev.partpay.co.nz");
            var createOrderRequest  = CreateRequest(CreateOrderRequest.PaymentFlowEnum.Payment);
            var createOrderResponse = instance.OrderCreate(authorization, "IK003", createOrderRequest);

            id = createOrderResponse.OrderId;

            System.Threading.Thread.Sleep(2000); // Give the system time to complete the creation of the order

            var order = instance.OrderGet(authorization, id);

            instance.OrderUpdateMerchantReference(order.OrderId, "new reference");

            System.Threading.Thread.Sleep(2000); // Give the system time to complete the update of the order

            var response = instance.OrderGet(authorization, id);

            Assert.AreEqual("new reference", response.MerchantReference, "response is Updated");
        }