public void TestAddItem()
        {
            //due to the complexity of the add items. we are going to create a known set of data points and add them to the collection.
              ShoppingCartItem si = new ShoppingCartItem();
              si.Description = "Description";
              si.DigitalContent = new DigitalItem("Digital Item Key", "Digital Item Description");
              si.MerchantItemID = "Merchant Item ID";
              si.MerchantPrivateItemData = "Private Data";

              XmlDocument mpdDoc = new XmlDocument();
              mpdDoc.LoadXml("<data />");
              mpdDoc.DocumentElement.AppendChild(mpdDoc.CreateElement("node1"));
              mpdDoc.DocumentElement.AppendChild(mpdDoc.CreateElement("node2"));
              XmlNode[] mpdNodes = new XmlNode[] { mpdDoc.DocumentElement.ChildNodes[0], mpdDoc.DocumentElement.ChildNodes[1] };

              si.MerchantPrivateItemDataNodes = mpdNodes;
              si.Name = "Name";
              si.Price = 0.99m;
              si.Quantity = 1;

              AlternateTaxTable taxTable = new AlternateTaxTable("Example");
              taxTable.AddStateTaxRule("OH", .06);

              si.TaxTable = taxTable;
              si.Weight = 10.5;

              si.TaxTable.AddCountryTaxRule(GCheckout.AutoGen.USAreas.ALL, 5.0);

              CheckoutShoppingCartRequest request = new CheckoutShoppingCartRequest(MERCHANT_ID, MERCHANT_KEY, EnvironmentType.Sandbox, "USD", 120);

              request.ContinueShoppingUrl = "http://localhost/";
              request.AnalyticsData = "Test data";
              request.PlatformID = 1234567890;
              request.EditCartUrl = "http://localhost/editcart.aspx";
              request.RequestBuyerPhoneNumber = true;
              request.MerchantCalculationsUrl = "http://localhost/calculate.aspx";
              request.AcceptMerchantCoupons = true;
              request.AcceptMerchantGiftCertificates = true;
              request.SetRoundingPolicy(RoundingMode.FLOOR, RoundingRule.TOTAL);
              request.AddShippingPackage("main", "Cleveland", "OH", "44114");

              request.MerchantPrivateData = "Test Cool Stuff";
              request.AddMerchantPrivateDataNode(mpdNodes[0]);

              XmlNode[] mpdn = request.MerchantPrivateDataNodes;

              Assert.AreSame(mpdn[0], mpdNodes[0]);

              try {
            request.AddItem(null);
            Assert.Fail("Null can't be passed to the AddItem methods");
              }
              catch {
              }

              try {
            MethodInfo mi = typeof(CheckoutShoppingCartRequest).GetMethod("AddItem", new Type[] { typeof(IShoppingCartItem) });
            mi.Invoke(request, new object[] { null });
            Assert.Fail("Null can't be passed to the AddItem methods");
              }
              catch {
              }

              request.AddItem(si);
              request.AddItem(si.Clone() as IShoppingCartItem);

              MethodInfo[] methods = typeof(CheckoutShoppingCartRequest).GetMethods();

              foreach (MethodInfo mi in methods) {
            bool cancel = false;
            //we are only working with AddItems
            if (mi.Name == "AddItem") {
              Type sct = typeof(ShoppingCartItem);
              ShoppingCartItem si2 = si.Clone() as ShoppingCartItem;
              ParameterInfo[] parameters = mi.GetParameters();
              object[] setter = new object[parameters.Length];
              for (int i = 0; i < parameters.Length; i++) {
            ParameterInfo pi = parameters[i];
            if (pi.ParameterType == typeof(ShoppingCartItem) || pi.ParameterType == typeof(IShoppingCartItem)) {
              cancel = true;
              continue;
            }
            //get the property from the object
            PropertyInfo source;
            if (pi.Name != "digitalItem") {
              source = sct.GetProperty(pi.Name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
            }
            else {
              source = sct.GetProperty("DigitalContent");
            }
            setter[i] = source.GetValue(si2, null);

            //we want to split and take the first item
            if (!pi.ParameterType.IsArray && source.PropertyType.IsArray) {
              object[] vals = setter[i] as object[];
              setter[i] = vals[0] as object;
            }
              }
              if (!cancel) {
            //now call the method
            ShoppingCartItem called = mi.Invoke(request, setter) as ShoppingCartItem;

            //this is to fix a params array issue.
            if (parameters[parameters.Length - 1].Name == "MerchantPrivateItemDataNodes") {
              called.MerchantPrivateItemDataNodes = si2.MerchantPrivateItemDataNodes;
            }
              }
            }
              }

              byte[] toXml = request.GetXml();

              //Make sure we can add an item to the cart.
              ShoppingCartItem item = request.AddItem("Item 1", "Cool Candy 1", "Merchant Item ID", 2.00M, 1);
              item.Weight = 2.2;
              item.MerchantPrivateItemData = null; //perform a null check

              //verify we can't set the price to fractions.

              item.Price = 1.975m;
              Assert.AreEqual(1.98m, item.Price);

              item.Price = 1.994m;
              Assert.AreEqual(1.99m, item.Price);

              Assert.AreEqual(2.2, item.Weight);
              Assert.AreEqual("Merchant Item ID", item.MerchantItemID);

              //this is a very specific test to make sure that if only one node exists, return it. it may be for a reason.

              XmlDocument doc = new XmlDocument();
              doc.LoadXml("<data />");
              doc.DocumentElement.SetAttribute("test", "cool");

              string xml = doc.OuterXml;
              item.MerchantPrivateItemDataNodes = new XmlNode[] { doc.DocumentElement };
              string xmlReturn = item.MerchantPrivateItemData;
              Assert.AreEqual(xml, xmlReturn);

              //create a new node
              XmlNode secondNode = doc.DocumentElement.AppendChild(doc.CreateElement("test"));
              item.MerchantPrivateItemDataNodes = new XmlNode[] { doc.DocumentElement, secondNode };

              xmlReturn = item.MerchantPrivateItemData;
              Assert.AreEqual(null, xmlReturn);

              item.MerchantPrivateItemDataNodes = null;
              Assert.AreEqual(new XmlNode[] { }, item.MerchantPrivateItemDataNodes);

              //this should throw an exception
              try {
            item.Weight = -1;
            Assert.Fail("Weight should not be allowed to be negative.");
              }
              catch {
              }

              //create a new instance of the cart item
              ShoppingCartItem testItem = new ShoppingCartItem();
        }