public void GetBillingInvoiceTest()
        {
            var os       = new OpenStackMember(UserName, Password, TenantName); // with tenant
            var invoices = os.ListBillingInvoices();

            Assert.IsNotNull(invoices);
            foreach (var i in invoices)
            {
                var invoice = os.GetBillingInvoice(i.InvoiceId);
                Assert.IsNotNull(invoice);
                Trace.WriteLine(string.Format("AccountId : {0}", invoice.AccountId));
                Trace.WriteLine(string.Format("BalanceBill : {0}", invoice.BalanceBill));
                Trace.WriteLine(string.Format("BalanceBillPlasTax : {0}", invoice.BalanceBillPlasTax));
                Trace.WriteLine(string.Format("Bill : {0}", invoice.Bill));
                Trace.WriteLine(string.Format("BillPlasTax : {0}", invoice.BillPlasTax));
                Trace.WriteLine(string.Format("BrandId : {0}", invoice.BrandId));
                Trace.WriteLine(string.Format("CreatedBy : {0}", invoice.CreatedBy));
                Trace.WriteLine(string.Format("CreatedDate : {0}", invoice.CreatedDate));
                Trace.WriteLine(string.Format("Currency : {0}", invoice.Currency));
                Trace.WriteLine(string.Format("DueDate : {0}", invoice.DueDate));
            }
        }