public void ShoulBuildFullUrl()
        {
            // arrange
            Transaction tx = new Transaction { Tx = "ABC", Amount = "123", ReturnUrl = "http://test.com" };

            // assert
            Assert.AreEqual("http://test.com?tx=ABC&st=&amt=123&cc=&cm=&item_number=&business=", tx.ToPdtReturnUrl());
        }