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Unit test for void method with Interface as parameter

New to Unit testing, I have below sample code and I want to create a unit test for this , Please suggest what should i do to create a unit test for this ? any link or pointers would be helpful to start
public class UserNotification : Work
{
public override void Execute(IWorkContext iwc)
{
throw new InvalidWorkException($"some message:{iwc.Name} and :{iwc.Dept}");
}
}
Edit: using MSTest for Unit testing

First, you need a test project alongside with your regular project.
You can pick from these three:
MSTest
nUnit
xUnit
All of these should have a project template in VS2022.
xUnit is a popular one, so let's pick that. The usual naming convention for test projects is YourProject.Tests. Rename UnitTest1.cs class to UserNotificationTests.cs.
As simple as it gets, you can now start writing your tests. In xUnit, a method with [Fact] attribute is a test method.
using Xunit;
namespace MyProject.Tests
{
public class UserNotificationTests
{
[Fact]
public void Execute_Should_Throw_InvalidWorkException_With_Message()
{
}
}
}
Don't think these methods as the methods in the code, naming should be close to English sentences and should reveal the intent as a regular sentence.
Classic approach to unit testing has three phases:
Arrange: Take instances of your objects, set your expected output, mock dependencies, make them ready.
Act: Call the actual action you want to test.
Assert: Check if how your actual output relates to your expected output.
Let's start with arranging.
We need a new instance of UserNotification class so we can call Execute().
We need any dummy IWorkContext object so we can pass it. We'll use NSubstitute library for that.
// Don't forget to add using NSubstitute
// Arrange
var userNotification = new UserNotification();
var workContext = Substitute.For<IWorkContext>();
workContext.Name = "testName";
workContext.Dept = "testDept";
Now you act, and invoke your method:
// Act
Action act = () => userNotification.Execute(workContext);
And lastly we assert. I highly recommend FluentAssertations library for asserting.
// Assert
act.Should().Throw<InvalidWorkException>()
.WithMessage($"some message:{workContext.Name} and :{workContext.Dept}");
Navigate to View > Test Explorer and run your tests, you should see something similar to this:
Congratulations, you wrote your first unit test.
Here's the final version of your test code:
using FluentAssertions;
using NSubstitute;
using System;
using Xunit;
namespace MyProject.Tests
{
public class UserNotificationTests
{
[Fact]
public void Execute_Should_Throw_InvalidWorkException_With_Message()
{
// Arrange
var userNotification = new UserNotification();
var workContext = Substitute.For<IWorkContext>();
workContext.Name = "testName";
workContext.Dept = "testDept";
// Act
Action act = () => userNotification.Execute(workContext);
// Assert
act.Should().Throw<InvalidWorkException>()
.WithMessage($"some message:{workContext.Name} and :{workContext.Dept}");
}
}
public class UserNotification : Work
{
public override void Execute(IWorkContext iwc)
{
throw new InvalidWorkException($"some message:{iwc.Name} and :{iwc.Dept}");
}
}
public abstract class Work
{
public virtual void Execute(IWorkContext iwc) { }
}
public interface IWorkContext
{
public string Name { get; set; }
public string Dept { get; set; }
}
public class InvalidWorkException : System.Exception
{
public InvalidWorkException() { }
public InvalidWorkException(string message) : base(message) { }
public InvalidWorkException(string message, System.Exception inner) : base(message, inner) { }
protected InvalidWorkException(
System.Runtime.Serialization.SerializationInfo info,
System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
}
}
Writing tests feels a lot different than writing regular code. But in time you'll get the hang of it. How to mock, how to act, how to assert, these may vary depending on what you are testing. The main point is to isolate the main thing you want to unit test, and mock the rest.
Good luck!

Because your title mentions specifically that you're trying to test a method with a void return type; I infer that you've already been testing methods with actual return values, and therefore that you already have a test project and know how to run a test once it is written. If not; the answer written by Mithgroth is a good explanation on how to get started on testing in general.
Your test is defined by the behavior that you wish to test. Your snippet has no behavior, which makes it hard to give you a concrete answer.
I've opted to rewrite your example:
public class UserNotification : Work
{
public override void Execute(IWorkContext iwc)
{
var splines = iwc.GetSplines();
iwc.Reticulate(splines);
}
}
Now we have some behavior that we want to test. The test goal is to answer the following question:
When calling Execute, does UserNotification fetch the needed splines and reticulate them?
When unit testing, you want to mock all other things. In this case, the IWorkContext is an external dependency, so it should be mocked. Mocking the work context allows us to easily configure the mock to help with the testing. When we run the test, we will pass an IWorkContext object which acts as a spy. In essence, this mocked object will:
... have been set up to return a very specific set of splines, one that we chose for the test's purpose.
... secretly record any calls made to the Reticulate method, and tracks the parameters that were passed into it.
Before we get into the nitty gritty on how to mock, we can already outline how our test is going to go:
[Test]
public void ReticulatesTheContextSplines()
{
// Arrange
IWorkContext mockedContext = ...; // This comes later
UserNotification userNotification = new UserNotification();
// Act
userNotification.Execute(mockedContext);
// Assert
// Confirm that Reticulate() was called
// Confirm that Reticulate() was given the result from `GetSplines()`
}
There's your basic unit test. All that's left is to create our mock.
You can write this yourself if you want. Simply create a new class that implements IWorkContext, and give it some more public properties/methods to help you keep track of things. A very simple example would be:
public class MockedWorkContext : IWorkContext
{
// Allows the test to set the returned result
public IEnumerable<Spline> Splines { get; set; }
// History of arguments used for calls made to Reticulate.
// Each call will add an entry to the list.
public List<IEnumerable<Spline>> ReticulateArguments { get; private set; } = new List<IEnumerable<Spline>>();
public IEnumerable<Spline> GetSplines()
{
// Returns the preset splines that the test configured
return this.Splines;
}
// Mocked implementation of Reticulate()
public void Reticulate(IEnumerable<Spline> splines)
{
// Does nothing except record what you passed into it
this.ReticulateArguments.Add(splines);
}
}
This is a very simplified implementation, but it gets the job done. The test will now look like this:
[Test]
public void ReticulatesTheContextSplines()
{
// Arrange
IEnumerable<Spline> splines = new List<Spline>() { new Spline(), new Spline() }; // Just create some items here, it's random test data.
IWorkContext mockedContext = new MockedWorkContext();
mockedContext.Splines = splines;
UserNotification userNotification = new UserNotification();
// Act
userNotification.Execute(mockedContext);
// Assert - Confirm that Reticulate() was called
mockedContext.ReticulateArguments.Should().HaveCount(1);
// Confirm that Reticulate() was given the result from `GetSplines()`
mockedContext.ReticulateArguments[0].Should().BeEquivalentTo(splines);
}
This test now exactly tests the behavior of your method. It uses the mocked context as a spy to report on what your unit under test (i.e. UserNotification) does with the context that you pass into it.
Note that I am using FluentAssertions here, as I find it the most easily readable syntax. Feel free to use your own assertion logic.
While you can write your own mocks; there are mocking libraries that help cut down on the boilerplating. Moq and NSubstitute are the two biggest favorites as far as I'm aware. I personally prefer NSubstitute's syntax; but both get the job done equally well.

If you want to use nunit the documentation with example is pretty easy to follow, link below.
Nunit documentation
And I think all other unit test framework have something similar to this.
[Test]
public void Execute_WhenCalled_ThrowArgumentException()
{
//Initialize an instance of IWorkContext
var iwc = new WorkContext();
//or use a Mock object, later on in assert use
//userNotification.Execute(iwc.Object)
var iwc = new Mock<IWorkContext>();
var userNotification = new UserNotification();
Assert.Throws(typeof(InvalidWorkException), () =>
{
userNotification.Execute(iwc)
});
}

How do I mock PolicyResult to contain a value for FinalException?

I have created an abstract class that implements Polly that I want to write unit tests for.
In one of my tests I want to test how my method handles certain values of PolicyResult.FinalException.
Because the returned PolicyResult is null I get a NullReferenceException when evaluating result.FinalException
How do I mock the returned result?
What I have so far:
public class AbstractRestClientTest
{
private AbstractRestClient _sut;
private Mock<IRestRequestFactory> _requestFactoryMock;
private Mock<IRestClientFactory> _restClientfactoryMock;
private Mock<IPollyPolicyFactory> _policyFactoryMock;
private Mock<IAsyncPolicy> _policyMock;
private const string DUMMY_URL = "http://dosomething.com/getmesomething";
[SetUp]
public void SetUp()
{
_requestFactoryMock = new Mock<IRestRequestFactory>();
_restClientfactoryMock = new Mock<IRestClientFactory>();
_policyFactoryMock = new Mock<IPollyPolicyFactory>();
var settings = new MockSettings();
_policyMock = new Mock<IAsyncPolicy>();
_policyFactoryMock.Setup(mock =>
mock.CreateAsyncResiliencePolicy(settings))
.Returns(_policyMock.Object);
_sut = new MockRestClient(settings, _restClientfactoryMock.Object,
_policyFactoryMock.Object,
_requestFactoryMock.Object);
}
}
public class MockRestClient : AbstractRestClient
{
public MockRestClient(RestSettings settings, IRestClientFactory restClientFactory, IPollyPolicyFactory pollyPolicyFactory,
IRestRequestFactory requestFactory) : base(settings, restClientFactory, pollyPolicyFactory, requestFactory) {
}
}
public class MockSettings : RestSettings
{
public override string Naam => "TestSettings";
}
------------------ EDIT 1 --------------------------------
With Nkosi's comment I got a little bit further but still PolicyResult returned by _policy.ExecuteAndCaptureAsync is null. This leads me to believe that there is something wrong in the way that I mock that method.
I changed my test to the following but still it returns `null``:
[Test]
public async Task HandleRequest_IfFinalExceptionNotNull_ThenThrowsException()
{
var mockResult = new Mock<IRestResponse<int>>();
PolicyResult<IRestResponse<int>> result = PolicyResult<IRestResponse<int>>.Failure(mockResult.Object, new Context());
//Is the following mock correctly setup?
_policyMock.Setup(mock => mock.ExecuteAndCaptureAsync(It.IsAny<Func<Task<IRestResponse<int>>>>()))
.ReturnsAsync(result);
var url = new Url(DUMMY_URL);
Assert.ThrowsAsync<Exception>(() => _sut.GetResult<int>(url));
}
I evaluated the parameters needed for ExecuteAndCapture and changed my setup for this method accordingly, what am I doing wrong?

Based on the publicly available source code on GitHub, there really is no need to mock that class. While it does have an internal constructor, static factory methods exist that should allow for the creation of your desired instance
For example
Context context = //...created as needed
PolicyResult<TestResponse> result = PolicyResult<TestResponse>.Failure(..., context);
Choose the right combination to satisfy the expected result in your test.

The issue was I was mocking the wrong version of ExecuteAndCaptureAsync, I needed to mock the method with the following signature:
`Task<PolicyResult> ExecuteAndCaptureAsync(Func<CancellationToken, Task> action, CancellationToken cancellationToken);`
So after I changes my SetUp accordingly the test succeeded:
[Test]
public async Task HandleRequest_IfFinalExceptionNotNull_ThenThrowsException()
{
var mockResult = new Mock<IRestResponse<int>>();
PolicyResult<IRestResponse<int>> result = PolicyResult<IRestResponse<int>>.Failure(mockResult.Object, new Context());
_policyMock.Setup(mock => mock.ExecuteAndCaptureAsync(
It.IsAny<Func<CancellationToken, Task<IRestResponse<int>>>>(),
It.IsAny<CancellationToken>()))
.ReturnsAsync(result);
var url = new Url(DUMMY_URL);
Assert.ThrowsAsync<Exception>(() => _sut.GetResultaat(url, new CancellationToken()));
}

Moq Method called by System.Threading.Tasks.Task.Factory.StartNew

I am using Moq to write a unit test. I have a DataManager object which calls WCF to fetch data. I inject this into my controller. however inside the controller the call to the Method in this DataManager is wrapped inside of a Task
System.Threading.Tasks.Task.Factory.StartNew<MyDataObject>(()=>
{
return DataManager.GetMyDataObject(userobj, recordid);
}
I have created a mock for the DataManager.GetMyDataObject with Moq
but whenever it is called from this statement inside of the controller method
it returns null. I have googled alot but most of the stuff out there are dealing with methods which have Task as the return signature.
The DataManager.GetMyDataObject is written as standard sync code.
I am using Moq v4.0.10827 and doubt I can upgrade.
I am trying many ways..Moq seems to expect the return to match the method signature
_mockDataManager = new Mock<_mockDataManager>();
_mockDataManager.Setup(m => m.GetMyDataObject(It.IsAny<UserObj>(), It.IsAny<Guid>()))
and well then returns? I also trid callback
_mockDataManager.Setup(m => System.Threading.Tasks.Task.FromResult(m.GetMyDataObject(It.IsAny<UserObj>(), It.IsAny<Guid>())
.Returns(System.Threading.Tasks.Task.FromResult(myData))
.Callback<MyDataObject>(o => myData = o);
myData = GetMyDataObject();
_mockDataManager.Setup(m => m.GetMyDataObject(It.IsAny<UserObj>(), It.IsAny<Guid>()).Returns(GetMyDataObject())
private GetMyDataObject() {
returns new DataSet(); //basically an empty dataset but not null
}

Given the following classes:
public class MyDataObject { }
public class UserObj { }
public class DataManager
{
public virtual MyDataObject GetMyDataObject(UserObj userObj, Guid guid)
{
throw new NotImplementedException();
}
}
class SUT
{
public DataManager DataManager { get; private set; }
public SUT(DataManager dataManager)
{
DataManager = dataManager;
}
public void Method(UserObj userobj, Guid recordid)
{
var t = System.Threading.Tasks.Task.Factory.StartNew<MyDataObject>(()=>
{
return DataManager.GetMyDataObject(userobj, recordid);
});
t.Wait();
}
}
the following mock works fine:
var mockDataManager = new Mock<DataManager>();
mockDataManager.Setup(m => m.GetMyDataObject(It.IsAny<UserObj>(), It.IsAny<Guid>()));
var sut = new SUT(mockDataManager.Object);
sut.Method(new UserObj(), Guid.Empty);
mockDataManager.VerifyAll();
Two pitfalls:
In the code you posted, you use
_mockDataManager = new Mock<_mockDataManager>();
which should be
_mockDataManager = new Mock<DataManager>(); // or whatever the name of the class is
Maybe this is just a copy/paste error, maybe not.
Also, since you use a Task here:
System.Threading.Tasks.Task.Factory.StartNew<MyDataObject>(()=>
{
return DataManager.GetMyDataObject(userobj, recordid);
}
which calls GetMyDataObject on DataManager, you have to make sure that the Task finished before you verify your mock setup. If you would remove the t.Wait(); from my code above, the test would fail, because VerifyAll would be called before the Task would start and call GetMyDataObject in the mocked object.

Error when using Machine.Specs to test class using MVC MailerBase

I'm receiving an error when I try to test a class (FindTask) that is making a call to another class (NotificationMailer) that inherits from MVC MailerBase.
System.ArgumentNullException: Value cannot be null.
Parameter name: httpContext
class FindTask
{
public void Find()
{
notificationMailer.Notify("Some message").Send();
}
}
I'm trying to verify that FindTask calls NotificationMailer::Notify.
public class NotificationMailer : MailerBase, INotificationMailer
{
public NotificationMailer()
{
MasterName = "_Layout";
}
public virtual MvcMailMessage Notify(string message)
{
return Populate(x =>
{
x.Subject = "Some Notification";
x.ViewName = "Notify";
x.To.Add("testEmail#test.com");
x.Body = message;
});
}
}
The error is on the return Populate(...) line.
public class FindTaskSpec : WithSubject<FindTask>
{
Establish context = () =>
{
MvcMailMessage mailMessage = new MvcMailMessage();
The<INotificationMailer>()
.WhenToldTo(x => x.Notify(Param<string>.IsAnything))
.Return(mailMessage);
};
Because of = () => Subject.Find();
}
public class when_something_is_found : FindTaskSpec
{
It should_send_an_email_with_the_found_stuff = () => The<IDeadLinkMailer>()
.WasToldTo(x => x.Notify(Param<string>.IsAnything))
.OnlyOnce();
}
I think the line in Establish context(the mock) should dictate that if Notify is called, it should return a new MVCMailMessage without running through the body of the function.
My Questions:
How can I resolve this error and test to make sure the Notify method is called?
Why is it that the mock for Notify does not stop the test from entering the function body of notify?
On a side note I've already tried setting MailerBase.IsTestModeEnabled = true. This results in an Url error - Invalid Url: The Url is Empty;
I've read through their wiki page on setting up tests for MvcMailer.
I've also read almost all the other stack overflow pages on this. I think that this link was most helpful. The problem is that I don't know how to imitate what they do in this link with Machine.Specifications.
I think my issue would be resolved if I could create a mock for either of the methods shown in the links.

I think in this situation I would be tempted to just create a FakeNotificationMailer class, by deriving from NotificationMailer and overriding the Notify method and having it return a pre-built MvcMailMessage. That's essentially the same as what your mock is doing, but everything is explicit. Something like:
public class FakeNotificationMailer : MailerBase, INotificationMailer
{
MvcMailMessage preBuiltMessage;
public NotificationMailer(MvcMailMessage result)
{
preBuiltMessage = result;
}
public virtual MvcMailMessage Notify(string message)
{
return preBuiltMessage;
}
}
(I had problems figuring out what your dependencies are, so that's a bit of a shot in the dark).
Of course then you have to find somewhere that you can inject your fake implementation (Dependency Inversion Principle).

Mocked Object Still Making Calls to Service

So I'm writing tests for our MVC4 application and I'm testing Controller actions specifically. As I mention in the title, the test still hits the service (WCF) instead of returning test data. I have this controller:
public class FormController : Controller
{
public SurveyServiceClient Service { get; set; }
public SurveyDao Dao { get; set; }
public FormController(SurveyServiceClient service = null, SurveyDao dao = null)
{
this.Service = service ?? new SurveyServiceClient();
this.Dao = dao ?? new SurveyDao(Service);
}
//
// GET: /Form/
public ActionResult Index()
{
var formsList = new List<FormDataTransformContainer>();
Dao.GetForms().ForEach(form => formsList.Add(form.ToContainer()));
var model = new IndexViewModel(){forms = formsList};
return View("Index", model);
}
And it uses this DAO object:
public class SurveyDao
{
private readonly SurveyServiceClient _service;
private readonly string _authKey;
public SurveyDao(SurveyServiceClient serviceClient)
{
_service = serviceClient;
}
....
public FormContract[] GetForms()
{
var forms = _service.RetrieveAllForms();
return forms;
}
And this is my test using JustMock, the mock on GetForms() returns some test data in a helper class:
[TestClass]
public class FormControllerTest
{
private SurveyDao mockDao;
private SurveyServiceClient mockClient;
public FormControllerTest()
{
mockClient = Mock.Create<SurveyServiceClient>();
mockDao = Mock.Create<SurveyDao>(mockClient);
}
[TestMethod]
public void TestIndexAction()
{
//Arrange
var controller = new FormController(mockClient, mockDao);
Mock.Arrange(() => mockDao.GetForms()).Returns(TestHelpers.FormContractArrayHelper);
//Act
var result = controller.Index() as ViewResult;
//Assert
Assert.IsInstanceOfType(result.Model, typeof(IndexViewModel));
}
}
My problem is that when I run the test, the Service is still being called. I've verified this using Fiddler as well as debugging the test and inspecting the value of "result" which is populated with our service's test data.
EDIT:
I've changed the test constructor to be a [TestInitialize] function, so the Test now looks like this:
[TestClass]
public class FormControllerTest
{
private SurveyDao mockDao;
private SurveyServiceClient mockClient;
[TestInitialize]
public void Initialize()
{
mockClient = Mock.Create<SurveyServiceClient>();
mockDao = Mock.Create<SurveyDao>(Behavior.Strict);
}
[TestMethod]
public void TestIndexAction()
{
//Arrange
var controller = new FormController(mockClient, mockDao);
Mock.Arrange(() => mockDao.GetForms()).Returns(TestHelpers.FormContractArrayHelper);
//Act
var result = controller.Index() as ViewResult;
//Assert
Assert.IsInstanceOfType(result.Model, typeof(IndexViewModel));
}
}

Please verify that you are using the correct assembly for JustMock. There are a few different ones (VisualBasic, Silverlight, JustMock). The JustMock one is the one you should be including in your project.
Failure to include the correct one will cause the behavior that you are describing (method not being properly stubbed).

The JustMock manual explains (highlights by me):
By default Telerik JustMock uses loose mocks and allows you to call
any method on a given type. No matter whether the method call is
arranged or not you are able to call it.
You can control this behavior when calling the Create() method of you Mock:
var foo = Mock.Create<IFoo>(Behavior.Strict);
There you can specify what the mock object should do if you have not explicitly implemented a certain method. In your case (I think it is the default behavior) the mock indeed calls the original method on the object that you want to mock.
You have the following choices in the Behavior Enumeration enumeration:
Loose: Specifies that by default mock calls will behave like a stub, unless explicitly setup.
RecursiveLoose: Specifies that by default mock calls will return mock objects, unless explicitly setup.
Strict: Specifies that any calls made on the mock will throw an exception if not explictly set.
CallOriginal: Specifies that by default all calls made on mock will invoke its corresponding original member unless some expecations are set.