We Keep Coding

Mock HttpResponseMessage while unit testing API with Moq and AutoFixture

I am writing unit tests for the existing Web API 2 project. For which i am using Ploeh Autofixture and Moq.
Test Method :
UPDATED
[Test]
public async Task Service1_TestMethod() {
//some code here
var fakeemail = FakeBuilder.Create<string>("test1234#test.com");
var fakeUserInvite =
FakeBuilder.Build<UserInvite>()
.With(i => i.EmailAddress, fakeemail)
.With(i => i.Username, fakeemail)
.Create();
var fakeUserToken = FakeBuilder.Create<string>();
var fakeHttpResponseMessage =
Fixture.Build<HttpResponseMessage>()
.With(h => h.StatusCode, HttpStatusCode.OK).Create();
//Here i am mocking another service method. Whose response is HttpResponseMessage.
Service2.Setup(i => i.AddUser(fakeUserInvite, fakeUserToken))
.ReturnsAsync(fakeHttpResponseMessage);
var result = await Service1.AddUser( /* */);
}
Service1 Method :
public async Task<bool> AddUser(/* */)
{
var response = await Service2.AddUser(userInvite, userToken); // response is null even after mocking it.
// Add user code follows bassed on the above response.
}
If i comment the Service2.AddUser call then everything works. There is a lot of code in that method apart from this call. I am having problem with only this call. If this call returns the mocked HttpResponseMessage then everything works.
Service2 is an external API. I am just wondering how to mock HttpResponseMessage. Any help is appreciated.

The stub you create with:
service2.Setup(i => i.AddUser(fakeUserInvite, fakeUserToken))
.ReturnsAsync(fakeHttpResponseMessage);
requires the actual call to be made with the exact same objects as the ones referenced by fakeUserInvite and fakeUserToken in order for Moq to return fakeHttpResponseMessage.
This is because Moq's argument matching verifies that the arguments specified in the stub are equal to the ones made in the actual call. If they are not, the stub won't match and Moq will return the default value for the method's return type – in this case null since HttpResponseMessage is a reference type.
To solve this problem, you can either make sure that the fakeUserInvite and fakeUserToken references are being passed to the actual service2.AddUser call or you can use somewhat less specific argument constraints.
Here's an example:
service2.Setup(i => i.AddUser(
It.Is<UserInvite>(u => u.EmailAddress == fakeEmail &&
u.Username == fakeEmail),
fakeUserToken))
.ReturnsAsync(fakeHttpResponseMessage);
Here we're stating that the AddUser method should be called with:
A UserInvite object whose EmailAddress and Username properties have the same value as fakeEmail as the first argument
The same value as fakeUserToken as the second argument
If the actual values of those arguments don't matter to your specific test scenario, you can tell Moq to always return fakeHttpResponseMessage regardless of what arguments AddUser is being called with by saying:
service2.Setup(i => i.AddUser(
It.IsAny<UserInvite>(),
It.IsAny<string>()))
.ReturnsAsync(fakeHttpResponseMessage);

Moq Test error Null on Service Layer

How can the following test be corrected to work?
[TestMethod()]
public void GetEmployeeProductivityTest()
{
var mockHR = new Mock<IRepository<Employee>>();
var mockCMS = new Mock<ICMS_Repository>();
mockCMS.Setup(repos => repos.FindEmployeeByUsername(It.IsAny<string>())).Verifiable();
Employee newEmp = new Employee();
newEmp.User_Name = "testName";
var service = new EmployeeService(mockHR.Object,mockCMS.Object);
var createResult = service.GetEmployeeByUserName(newEmp);
Assert.AreEqual(newEmp, createResult);
mockCMS.VerifyAll();
}
I get the following:
Assert.AreEqual failed. Expected:<Employee>. Actual:<(null)>.
As Requested this is the GetEmployeeByUserName() function being called:
public Employee GetEmployeeByUserName(Employee employee)
{
return _employeeRespository.Find().ByUserName(employee); <------(Using Strict: Gives me the following: All invocations on the mock must have a corresponding setup.)
}

Since you edited your question to show the behaviour of the GetEmployeeByUserName, it's now easy to explain why your test was failing.
mockCMS.Setup(repos => repos.FindEmployeeByUsername(It.IsAny<string>()))
Here you set up an expectation that the FindEmployeeByUsername(string) overload would be called, but then you go on to use the FindEmployeeByUsername(Employee) overload. Moq setups are for specific overloads so when the method is called the mocked service finds no matching setup. If there is no matching setup, the mock either returns the default value for the Employee type (null), or throws an exception, depending on which MockBehavior you chose.
In your updated test, you fixed this by setting up the overload that you actually use.
mockCMS.Setup(repos => repos.FindEmployeeByUsername(It.IsAny<Employee>()))
With simple methods like your GetEmployeeByUserName, mocking the dependencies and unit testing it can seem like a lot of overhead. What your test says is basically,
"when someone calls the GetEmployeeByUserName method on the EmployeeService,
the service should call the correct method on its repository"
Is this an important thing to assert? That's up to you to decide. As the complexity of your service methods increases, however, being able to isolate the dependencies and test their interactions will become more and more valuable.

You need to seed the FindEmployeeByUsername() Method of your mock:
mockCMS.Setup(repos => repos.FindEmployeeByUsername(It.IsAny<string>())).Returns(newEmp);
otherwise it wont return the expected object, while called within the EmployeeService.

Instead of using multiple repositories which I think was confusing. I simplified it and it works now! Except I'm still not sure how this helps me code better. What did I accomplish with this? (I'm new to Testing/Moq/Integration Tests...etc..) I would really like an answer...to this..
public void GetEmployeeUsername_Using_EmployeeClass()
{
var mockCMS = new Mock<ICMS_Repository>(MockBehavior.Strict);
Employee newEmp = new Employee();
newEmp.User_Name = "testName";
mockCMS.Setup(repos => repos.FindEmployeeByUsername(It.IsAny<Employee>())).Returns(newEmp);
var service = new EmployeeService(mockCMS.Object);
var createResult = service.GetEmployeeByUserName(newEmp);
Assert.AreEqual(newEmp, createResult);
}

What is the correct way to test this code using MOQ?

I have the following method:
public void MoveChannelUp(string channelName)
{
var liveChannels = _repository.GetChannels<LiveChannel>();
var channels = GetModifiedChannelsList(channelName, liveChannels);
_repository.SaveChannels(channels);
}
I want to set up an expectation on the SaveChannels() call so that the correct channels parameter is passed in.
I tried :
channelsRepository.Setup(x => x.SaveChannels(reorderedChannels));
where reorderedChannels is what I expect the GetModifiedChannelsList() call will return and but I got Mock verification exception (probably due to reorderedChannels is not the same object as channels???)
So it is GetModifiedChanneslsList() which I really want to test (I know I can use reflection to test this)
So how do I test the correct channels list is passed to SaveChannels()?

You can do something like this (I assume there is a type called Channel and the parameter for SaveChannels is List<Channel>; substitute with the actual):
var expectedChannels = new List<Channel> { new Channel() }; // set up expected channels here
var channelsRepo = new Mock<IChannelsRepository>();
// perform your unit test using channelsRepo here, for example:
channelsRepo.Object.SaveChannels(new List<Channel> { new Channel() });
channelsRepo.Verify(x => x.SaveChannels(It.Is<List<Channel>>(l => l.SequenceEqual(expectedChannels)))); // will throw an exception if call to SaveChannels wasn't made, or the List of Channels params did not match the expected.
What this code does is verify that the SaveChannels method is called at least once with the right list of channels. If that does not happen, Verify will throw an exception and your unit test will fail as expected.

Setting up moq and verifying that a method was called

Using Microsoft Test Framework and Moq I'm trying to verify if a log4net method was called.
[TestMethod()]
public void Log_Info_When_Stuff_Is_Done()
{
SampleClass sampleObject = new SampleClass();
Mock<log4net.ILog> logMockObject = new Mock<log4net.ILog>();
sampleObject.Log = logMockObject.Object;
sampleObject.DoStuffAndLogInfo();
logMockObject.Verify(moqLog => moqLog.Info("do stuff got called"), Times.AtLeastOnce());
}
I get an exception on Verify call saying that
Expected invocation on the mock at least once, but was never
performed: moqLog => moqLog.Info("do stuff got called") No setups
configured. No invocations performed.
What am I doing wrong?
update the problem was with a getter for SampleClas.Log property. I was always returning LogManager.GetLogger(...); even when the property was already set to a ILogProxy. I was under impression that the property's get accessor won't be called because I've set up a proxy like so sampleObject.Log = logMockObject.Object;

Right now Moq is verifying that DoStuffAndLogInfo calls Info with the exact string "do stuff got called". If it's actually calling Info with a different argument, and you don't care what the actual argument is, use the following instead:
logMockObject.Verify(moqLog => moqLog.Info(It.IsAny<string>()), Times.AtLeastOnce());

The test is correctly set up.
Check your sut to see if Log.Info actually gets called inside the DoStuffAndLogInfo method.

This doesn't look to be the original poster's problem, but in my case I had a very similar error message. It was due to my .Verify() call before the actual execution. For example, this is wrong:
SampleClass sampleObject = new SampleClass();
Mock<log4net.ILog> logMockObject = new Mock<log4net.ILog>();
logMockObject.Verify(moqLog => moqLog.Info(It.IsAny<string>()), Times.AtLeastOnce());
sampleObject.Log = logMockObject.Object;
sampleObject.DoStuffAndLogInfo();
....but this is right:
SampleClass sampleObject = new SampleClass();
Mock<log4net.ILog> logMockObject = new Mock<log4net.ILog>();
sampleObject.Log = logMockObject.Object;
sampleObject.DoStuffAndLogInfo();
logMockObject.Verify(moqLog => moqLog.Info(It.IsAny<string>()), Times.AtLeastOnce());

What is the right way to mock void functions in RhinoMocks?

I have this interface that returns void in some functions that I would like to mock and wonder what is the correct way of doing so. As of now I have the following:
var mocks = new MockRepository();
var mockedInterface = mocks.CreateMock<IMyInterface>();
Expect.Call(mockedInterface.FunctionThatReturn(param1, param2)).Return(Something);
mockedInterface.FunctionReturningVoid(param3, param4);
mocks.ReplayAll();
// Some assert and other stuff
mocks.VerifyAll();
Is that the right way of doing it? I think it looks weird since you're not handling the two functions the same way. What I would like to write is:
var mocks = new MockRepository();
var mockedInterface = mocks.CreateMock<IMyInterface>();
Expect.Call(mockedInterface.FunctionThatReturn(param1, param2)).Return(Something);
Expect.Call(mockedInterface.FunctionReturningVoid(param3, param4)); // This doesn't work.
mocks.ReplayAll();
// Some assert and other stuff
mocks.VerifyAll();
But that doesn't work on row 4. I found some blog that says you can use lambdas (or delegate) like
Expect.Call(() => mockedInterface.FunctionReturningVoid(param3, param4)); // This doesn't work.
But that doesn't seem to work either for me. Having the Expect.Call makes it easy to identify mocked functions and that is why I want it. The compile error I get is: "Cannot convert lambda expression to type 'object' because it is not a delegate type".
So how should it be done?
UPDATE: Added compile error information.

I prefer the AAA (arrange/act/assert) syntax instead of record/replay. It's more straightforward and makes the tests easier to read. What you'll want to do is:
// arrange
var mock = MockRepository.GenerateMock<IMyInterface>
mock.Expect(i => i.FunctionThatReturnSomething(param1, param2)).Return("hello");
mock.Expect(i => i.FunctionThatReturnVoid(param3, param4));
// set up other stuff for your code (like whatever code depends on IMyInterface)
var foo = new Foo(mock);
// act
foo.DoSomething();
// assert
mock.VerifyAll();

For void methods I use anonymous delegates:
Expect.Call(delegate { mockedInterface.FunctionReturningVoid(param3, param4); })
BTW: I like Record-Playback syntax for replaying and verifying expectations
http://www.ayende.com/Wiki/(S(j2mgwqzgkqghrs55wp2cwi45))/Comparison+of+different+Rhino+Mocks+syntaxes.ashx

Not sure how to test void method in AAA pattern, I was also having trouble mocking void. However, in the past, I use the Record and Playback style, and that should work.
Example:
private MockRepository m_mocks = new MockRepository();
private IXGateManager xGateManager = m_mocks.DynamicMock<IXGateManager>();
using (m_mocks.Record())
{
xGateManager.SendXGateMessage(null, null);
LastCall.IgnoreArguments().Repeat.Once();
}
using (m_mocks.Playback())
{
//... execute your test
}