public void TestSimple() { cancelSubscription update = new cancelSubscription(); update.subscriptionId = 12345; var mock = new Mock <Communications>(); mock.Setup(Communications => Communications.HttpPost(It.IsRegex(".*<cnpOnlineRequest.*?<cancelSubscription>\r\n<subscriptionId>12345</subscriptionId>\r\n</cancelSubscription>\r\n</cnpOnlineRequest>.*?.*", RegexOptions.Singleline))) .Returns("<cnpOnlineResponse version='8.20' response='0' message='Valid Format' xmlns='http://www.vantivcnp.com/schema'><cancelSubscriptionResponse><subscriptionId>12345</subscriptionId></cancelSubscriptionResponse></cnpOnlineResponse>"); Communications mockedCommunication = mock.Object; cnp.SetCommunication(mockedCommunication); cnp.CancelSubscription(update); }