public void ServiceResult_AppendErrorMessage_InitialSuccessResult_NewResult() { ServiceResult <object> initialResult = ServiceResult <object> .CreateSuccessResult(new object()); ServiceResult <object> result = null; string errorMessage = "error"; Assert.DoesNotThrow(() => result = initialResult.AppendErrorMessage(errorMessage)); Assert.IsNotNull(result); Assert.IsInstanceOf(typeof(object), result.Result); Assert.IsTrue(result.IsErrored); Assert.IsNotNull(result.Result); Assert.AreEqual(errorMessage, result.ErrorMessage); }