public override void DoTest()
        {
            var si = new IntegrationService();
            PurchaseInvoiceWrapper item;
            var path       = @"Data\PurchaseInvoiceWrapper.xml";
            var serialiser = new XmlSerializer(typeof(PurchaseInvoiceWrapper));

            using (TextReader reader = new StreamReader(path))
            {
                item = (PurchaseInvoiceWrapper)serialiser.Deserialize(reader);
                reader.Close();
            }

            var results = si.ReceiptLoad(item);
        }