模拟函数在c#单元测试中不抛出异常

Question

Here is my unit test method

        [Fact]
        public void DealerSmsStatusTestTest_MustReturnInternalServerErrorIfMockMethodFails()
        {
            //Arrange
            Mock<DBClass.IDealer> mock = new Mock<DBClass.IDealer>();
            var exception = FormatterServices.GetUninitializedObject(typeof(System.Data.SqlClient.SqlException));
            mock.Setup(x => x.GetDealerStatus(new System.Net.Http.HttpRequestMessage()))
                .Throws((System.Data.SqlClient.SqlException)exception);

            DealerSettingController controller = new DealerSettingController(mock.Object);
            
            //Act
            var result = controller.DealerSmsStatus();
   
            //Assert
         /*I will do assertion here*/

        }

And here is my controller method

public IHttpActionResult DealerSmsStatus()
        {
            try
            {
                var result = _dealer.GetDealerStatus(Request);
                return Json(new Models.Response(
                            Models.ResponseMessages.Success,
                            result)
                         );
            }
            catch (System.Data.SqlClient.SqlException)
            {
                return InternalServerError();
            }
            catch (System.Exception ex)
            {
                Logger.Error(ex, ex.Message, ex.StackTrace);
                return InternalServerError();
            }

        }

When i debug the test, GetDealerStatus() method should return SqlException instead it returns null . In controller method var result always getting null . Any suggestions appreciated why it is not working.I want to throw SqlException through GetDealerStatus() . Here is debug mode result value image

Answer 1

You should use It.IsAny<System.Net.Http.HttpRequestMessage>() instead of new System.Net.Http.HttpRequestMessage() at Setup . Because you configured your method for concrete instance of System.Net.Http.HttpRequestMessage , at test it's not the same.

Answer 2

It's probably the matcher x.GetDealerStatus(new System.Net.Http.HttpRequestMessage())

new System.Net.Http.HttpRequestMessage() creates a new instance of a HttpRequestMessage which will not be equal to the Request you're passing into GetDealerStatus in your SUT.

Normally you'd use something like:

x.GetDealerStatus(It.IsAny<System.Net.Http.HttpRequestMessage>())

or

It.Is<System.Net.Http.HttpRequestMessage>(x => whatever specific equality conditions you want to match on)

if you want to narrow the match condition from just 'any'