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How to Mock an nested service

I'm trying to mock using Moq, xUnit,.Net 6, Entity framework Core, I have this service:
public class CompanyService : ICompanyService
{
private readonly ICompanyRepository _repository;
public CompanyService(ICompanyRepository repository)
{
_repository = repository;
}
public async Task<Company> Create(Company Company) => await _repository.Create(Company);
}
this is the company service interface:
public interface ICompanyService
{
Task<Company> Create(Company Company);
}
this is my company repository class:
public class CompanyRepository : ICompanyRepository
{
private readonly ApplicationDbContext _context;
public CompanyRepository(ApplicationDbContext context)
{
_context = context;
}
public async Task<Company> Create(Company Company)
{
Company.Id = Guid.NewGuid();
await _context.Companies.AddAsync(Company);
await _context.SaveChangesAsync();
return Company;
}
}
and this is its interface:
public interface ICompanyRepository
{
Task<Company> Create(Company Company);
}
this is my DbContext:
public class ApplicationDbContext : DbContext
{
public ApplicationDbContext(DbContextOptions options): base(options)
{}
public DbSet<Company> Companies { get; set; }
}
and finally this is my class for testing:
public class CompanyServiceTest
{
private readonly CompanyService _sut;
private readonly Mock<ICompanyRepository> _companyRepositoryMock = new Mock<ICompanyRepository>();
public CompanyServiceTest()
{
_sut = new CompanyService(_companyRepositoryMock.Object);
}
[Fact]
public async void CreateACompanyShouldWorks()
{
//Arrange
var CompanyEntity = new Company();
CompanyEntity.Name = "Test Company";
//Act
var companyCreated = await _sut.Create(CompanyEntity);
//Assert
Assert.NotNull(companyCreated);
_companyRepositoryMock.Verify(r => r.Create(CompanyEntity));
}
}
but when I run the test I get this message error:
"Assert.NotNull() Failure"
Stack Trace: 
CompanyServiceTest.CreateACompanyShouldWorks() line 31
<>c.b__128_0(Object state)
I don't know if I have to mock the ApplicationDbContext, or if I have to mock anything else, I'm Using xUnit, .Net 6, Entity framework core, also I have downloaded the Moq package.

You just forgot to setup the mock inside the Arrange phase
_companyRepositoryMock
.Setup(r => r.Create(It.IsAny<CompanyEntity>()))
.ReturnsAsync(expectedCompany);
OR
_companyRepositoryMock
.Setup(r => r.Create(It.IsAny<CompanyEntity>()).Result)
.Returns(expectedCompany);
If you don't setup the mock then it will return the default value.
If you change the MockBehaviour to strict then it will throw exception.
UPDATE #1
in the case of the method GetAllCompanies I have to create a List<Company>() and then return them ? and in the method GetCompanyById I have to create an object of Company and returns it ? I mean xUnit does not go to the database using my repository?
The short answer is yes you have to mock all the methods that you want to use on your dependency. Since the CompanyService is relying correctly on abstraction (ICompanyRepository interface) rather than on the implementation (CompanyRepository class) that's why you are not depending on the Entity Framework directly.
If you want to test your repository tier/layer/module than you have to mock the DbContext to avoid database calls. There are tons of nuget packages which can be used to ease the mocking burden.

This is the solution:
//Arrange
var CompanyEntity = new Company();
CompanyEntity.Name = "Test Company";
CompanyEntity.Id = Guid.NewGuid();
CompanyEntity.Employees = new HashSet<Employee>();
//arrange
_companyRepositoryMock
.Setup(r => r.Create(It.IsAny<Company>()))
.ReturnsAsync(CompanyEntity);
//Act
var companyCreated = await _sut.Create(CompanyEntity);
//Assert
Assert.NotNull(companyCreated);
_companyRepositoryMock.Verify(r => r.Create(companyCreated));

Mocked method do not pass correct value

I am trying to understand how mocking works in Xunit with AutoFixture. I have created Service and Repository classes and their interfaces. Mocked method should pass value which is different from default value.
Mocked method always pass default values instead of values which i am writing in ".Returns()". I have tried AutoConfiguredMoqCustomization but it provides completely random values which i can't get back.
Repository.cs
public class Repository : IRepository
{
public int GetInt()
{
return 999;
}
}
Service.cs
public class Service : IService
{
private readonly Repository _repository;
public Service()
{
_repository = new Repository();
}
public string GetStringFromInt()
{
return _repository.GetInt().ToString();
}
}
Test
[Fact]
public void Test()
{
var fixture = new Fixture().Customize(new AutoMoqCustomization());
var repositoryMock = fixture.Create<Mock<IRepository>>();
var service = fixture.Create<Service>();
repositoryMock.Setup(x => x.GetInt()).Returns(1);
var act = service.GetStringFromInt();
Assert.Equal("1", act);
}
As you see value by default in Repository is 999 and I am expecting 1 from repositoryMock but result is "999" instead of "1".
Ow I have understood my problem. When I declare parameters with auto moq testing service must be AFTER all mocked repositories
Test
[Theory, AutoMoqData]
public void Test([Frozen] Mock<IRepository> repositoryMock, Service service)
{
...
}
Attribute
public class AutoMoqDataAttribute : AutoDataAttribute
{
public AutoMoqDataAttribute() : base(GetDefaultFixture)
{
}
private static IFixture GetDefaultFixture()
{
return new Fixture().Customize(new AutoMoqCustomization());
}
}

You should freeze your mock first. When you call Create on AutoFixture, it will create you a new instance every time. Try the following in the modified code (where you are using an interface of the type in your constructor).
public class ServiceTests
{
private readonly IFixture fixture = new Fixture().Customize(new AutoMoqCustomization());
public ServiceTests()
{
fixture.Register<IService>(() => fixture.Create<Service>());
}
[Fact]
public void Test()
{
// Arrange
var repositoryMock = fixture.Freeze<Mock<IRepository>>();
repositoryMock.Setup(x => x.GetInt()).Returns(1);
var service = fixture.Create<IService>();
// Act
var act = service.GetStringFromInt();
// Verify
Assert.Equal("1", act);
}
}
To check that you have set up autofixture correctly, you can try the following in the unit test in future.
var repo1 = fixture.Create<IRepository>();
var repo2 = fixture.Create<IRepository>();
Assert.Equal(repo1.GetHashCode(), repo2.GetHashCode());
If the above fails, that indicates that you have not frozen a type. These lines of code have saved me so much head scratching in the past...

You are doing DI wrong, you are not injecting Repository into Your serice.
Try like this.
public class Repository : IRepository
{
public int GetInt()
{
return 999;
}
}
public class Service : IService
{
IRepository Repository;
public Service(IRepository repository)
{
this.Repository = repository;
}
public string GetStringFromInt()
{
return Repository.GetInt().ToString();
}
}
Now when you mock IRepository, you can add it to Service.
You are using a new Repository() in constructor, so you are using that implementation

Moq: setup a generic method with mocked parameters

I've been trying to write a few tests in NUnit for my generic methods, without success. I hope I can make my situation clear, since I had to heavily paraphrase my code.
DoBusinessLogic() is the method I want to test. It calls two other methods from the base class:
public class MySvc : BaseSvc, IMySvc
{
private readonly IMyRepo _repo;
private readonly IMyConnectorClass _connector
public MySvc(IMyRepo repo) : base(repo)
{
_repo = repo;
_connector = _repo.GetConnector();
}
public async Task DoBusinessLogic(int id1, int id2){
bool doesFirstObjectExist = await CheckMainObjExists<Foo>(id1, _connector);
await CheckSubObjExists<Bar>(id2, _connector);
// further business logic
}
}
Those methods, in turn, call the same repository method, but have different logic after it:
public abstract class BaseSvc : IBaseSvc
{
private readonly IBaseRepo _repo
protected BaseSvc(IBaseRepo repo)
{
_repo = repo;
}
protected async Task<bool> CheckMainObjExists<T>(int? id, IMyConnectorClass connector)
{
return await _repo.GetObjectByIdAsync<T>(Id, connector) != null;
}
protected async Task CheckSubObjExists<T>(int? id, IMyConnectorClass connector)
{
if (await _repo.GetObjectByIdAsync<T>(Id, connector) == null)
{ throw new Exception("Object not found!"); }
}
}
Next, I want to write unit a test for DoBusinessLogic() in the MySvc class. Unfortunately, it seems I can't mock the responses from the repository.
[TestFixture]
public class MySvcTests
{
private MySvc _svc;
private Mock<IMyRepo> _repoMock;
private Mock<IMyConnectorClass> _connectorMock;
[SetUp]
public void SetUp()
{
_repoMock = new Mock<IMyRepo>() {};
_connectorMock = new Mock<IMyConnectorClass>();
_repo.SetUp(r => r.GetConnector()).Return(_connectorMock.Object);
_svc = new MySvc(_repoMock);
}
/*
My intent in this test, is to make CheckMainObjExists() pass,
but make CheckSubObjExist() fail.
*/
[Test]
public async Task DoBusinessLogic_If2ndObjectNotExist_ThrowException()
{
// This should return an object
_repoMock.Setup(r => r.GetObjectByIdAsync<Foo>(It.IsAny<int>(), _connectorMock.Object))
.ReturnsAsync(new Foo());
// This should return null
_repoMock.Setup(r => r.GetObjectByIdAsync<Bar>(It.IsAny<int>(), _connectorMock.Object))
.ReturnsAsync((Bar) null);
Assert.Throws<Exception>(await _svc.DoBusinessLogic());
}
}
However, when I run the test, both methods that I set up for my mock repo return null, whereas I expect a "true" from the first.
I do not know where the problem is situated, but I have my suspicions:
Is it possible to setup a method, using a mocked object as a parameter? In this case, is it possible to use _connectorMock.Object as a setup parameter?
Is it possible to setup the same generic method multiple times, but for a different type each time? It's first setup for Foo, then for Bar.

I just tested this code and it runs as expected. Now I had to make a lot of assumptions just to get the code to compile and run which would mean that my test of your code is flawed as I may have fixed something that was omitted in your example.
I made no changes to your test setup code, which worked.
[TestClass]
public class MySvcTests {
[TestMethod]
[ExpectedException(typeof(Exception))]
public async Task DoBusinessLogic_If2ndObjectNotExist_ThrowException() {
var _repoMock = new Mock<IMyRepo>() { };
var _connectorMock = new Mock<IMyConnectorClass>();
_repoMock.Setup(r => r.GetConnector()).Returns(_connectorMock.Object);
var _svc = new MySvc(_repoMock.Object);
// This should return an object
_repoMock.Setup(r => r.GetObjectByIdAsync<Foo>(It.IsAny<int>(), _connectorMock.Object))
.ReturnsAsync(new Foo());
// This should return null
_repoMock.Setup(r => r.GetObjectByIdAsync<Bar>(It.IsAny<int>(), _connectorMock.Object))
.ReturnsAsync((Bar)null);
await _svc.DoBusinessLogic(0, 0);
}
}

TableControllers Unit test

So I'm trying to write a simple tablecontroller Unit test for my backend??
I havent been able to do so, all I've achieve is writing unit testing for ApiControllers but is there a way to write a Unit test for TableControllers?
What I'll like to do is this:
public class AuctionController : TableController<Auction>
{
protected override void Initialize(HttpControllerContext controllerContext)
{
base.Initialize(controllerContext);
MobileServiceContext context = new MobileServiceContext();
DomainManager = new EntityDomainManager<Auction>(context, Request);
}
// GET tables/Auction
public IQueryable<Auction> GetAllAuction()
{
return Query();
}
// GET tables/Auction/48D68C86-6EA6-4C25-AA33-223FC9A27959
public SingleResult<Auction> GetAuction(string id)
{
return Lookup(id);
}
// PATCH tables/Auction/48D68C86-6EA6-4C25-AA33-223FC9A27959
public Task<Auction> PatchAuction(string id, Delta<Auction> patch)
{
return UpdateAsync(id, patch);
}
// POST tables/Auction
public async Task<IHttpActionResult> PostAuction(Auction item)
{
Auction current = await InsertAsync(item);
return CreatedAtRoute("Tables", new { id = current.Id }, current);
}
// DELETE tables/Auction/48D68C86-6EA6-4C25-AA33-223FC9A27959
public Task DeleteAuction(string id)
{
return DeleteAsync(id);
}
}
and i wish to make a test controller like this one:
[TestClass]
public class AuctionControllerTests
{
private readonly AuctionController _controller;
public AuctionControllerTests()
{
_controller = new AuctionController();
}
[TestMethod]
public void Fetch_all_existing_items()
{
Assert.Equal(2, _controller.GetAllTodoItems().ToList().Count);
}
}
how can I possibly be able to get this to work??? Please I would appreciate your help a lot.

Yes. it is possible but you code is not unit testable. Here are the steps for you
Find a way inject your depedencies MobileServiceContext and DomainManager
You need to set up contexts and requests etc as in shown in the following code.
(Code assumes you are using Moq)
public class ControllerUnitTestBase<T> where T: Controller
{
private Action<RouteCollection> _routeRegistrar;
private Mock<HttpRequestBase> _mockRequest;
protected virtual Action<RouteCollection> RouteRegistrar
{
get { return _routeRegistrar ?? DefaultRouteRegistrar; }
set { _routeRegistrar = value; }
}
protected Mock<HttpRequestBase> MockRequest
{
get
{
if (_mockRequest == null)
{
_mockRequest = new Mock<HttpRequestBase>();
}
return _mockRequest;
}
}
public abstract T TargetController { get; }
protected void TargetSetup()
{
var routes = new RouteCollection();
RouteRegistrar(routes);
var responseMock = new Mock<HttpResponseBase>();
responseMock.Setup(x => x.ApplyAppPathModifier(It.IsAny<string>())).Returns((string url) => url);
var contextMock = new Mock<HttpContextBase>();
contextMock.SetupGet(x => x.Request).Returns(MockRequest.Object);
contextMock.SetupGet(x => x.Response).Returns(responseMock.Object);
contextMock.SetupGet(x => x.Session).Returns(Mock<HttpSessionStateBase>().Object);
TargetController.ControllerContext = new ControllerContext(contextMock.Object, new RouteData(), TargetController);
TargetController.Url = new UrlHelper(new RequestContext(contextMock.Object, new RouteData()), routes);
}
protected void DefaultRouteRegistrar(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional });
}
}
Inherit from this code and make sure you call TargetSetup() before test execution ( maybe in test initialization (setup). And you are good to go as in:
[TestClass]
public class AuctionControllerTests: TestControllerBase<AuctionController>
{
public AuctionController TargetController {
get {return new AuctionController();//inject your mocked dependencies}}
[TestInitialize]
public void SetUp()
{
TargetSetup()
}
}

So Thanks for the mocking solution, It worked but I wrote a generic better solution without using mocking framework, I'll apply mocking framework later, right now I'll stick with fakes and real dbs for integration tests.
but firstable I wrote a Generic TableController in order to apply multiple EntityData and DbContext for those who had more than one Context, also you could apply a FakeContext thanks to the abstraction of interfaces but i havent applied to this example.
First This is my BaseController:
//This is an abstract class so we can apply inheritance to scalfolded tablecontrollers<T>.
public abstract class BaseController<TModel, TDbContext> : TableController<TModel> where TModel : class, ITableData
where TDbContext:DbContext, new()
{
protected override void Initialize(HttpControllerContext controllerContext)
{
base.Initialize(controllerContext);
var context = new TDbContext();
SetDomainManager(new EntityDomainManager<TModel>(context, Request));
}
public void SetDomainManager(EntityDomainManager<TModel> domainManager)
{
DomainManager = domainManager;
}
}
this is my scalfolded controller with my basecontroller applied!!!
public class AuctionController : BaseController<Auction, MobileServiceContext>
{
public IQueryable<Auction> GetAllAuction()
{
return Query();
}
// GET tables/Auction/48D68C86-6EA6-4C25-AA33-223FC9A27959
public SingleResult<Auction> GetAuction(string id)
{
return Lookup(id);
}
// PATCH tables/Auction/48D68C86-6EA6-4C25-AA33-223FC9A27959
public Task<Auction> PatchAuction(string id, Delta<Auction> patch)
{
return UpdateAsync(id, patch);
}
// POST tables/Auction
public async Task<IHttpActionResult> PostAuction(Auction item)
{
Auction current = await InsertAsync(item);
return CreatedAtRoute("Tables", new { id = current.Id }, current);
}
// DELETE tables/Auction/48D68C86-6EA6-4C25-AA33-223FC9A27959
public Task DeleteAuction(string id)
{
return DeleteAsync(id);
}
}
With my generic application I can apply any DbContext that way you could even apply FakeDbContexts in order to avoid SqlConnection or Cloud connection such as Azure which is the one I used in this example.
UPDATED MARCH 14th, 2018
All this two library are on my Backend project, now I'll show you my test project in order to Unit Test a TableController
public abstract class ControllerTestBase<TController, TModel, TDbContext> where TController : BaseController<TModel, TDbContext>, new()
where TModel : class, ITableData
where TDbContext: DbContext, new()
{
protected readonly TController Controller;
protected ControllerTestBase()
{
Controller = new TController();
Controller.Configuration = new HttpConfiguration();
Controller.Request = new HttpRequestMessage();
var context = new TDbContext();
Controller.SetDomainManager(new EntityDomainManager<TModel>(context, Controller.Request));
}
}
Ok thanks to this abstract class you can supress the initialize setup from the testing library because each time you run a test it will call the generic test constructor, setting up all the necessary requierements and thus avoid ArgumentNullExceptions and InvalidOperationExceptions such common problem for unit testing tablecontroller since isnt quite intuitive to initialize as an ApiController.
Finally if you modify this then you can run a test like this:
[TestClass]
public class AuctionControllerTest : ControllerTestBase<AuctionController, Auction, MobileServiceContext>
{
[TestMethod]
public void Fetch_All_Existing_Items()
{
Assert.AreEqual(1, Controller.GetAllAuction().ToList().Count);
}
}
thanks to my generic application you can now use this code as an example to be apply to your TableControllers and also if you follow the Interface Segregation Principle you could apply FakeDbContext to your Controllers.
For those who helped me thanks you opened my mind into coming with this solution!!!

passing mocked parameter to mocked interface

I am using nuit with moq to test my controllers.
I use a session class which has an interface and an HttpContext is injected into the constructor using ninject.
like this
public class SessionService : ISession
{
public HttpContext Context { get; set; }
public SessionService(HttpContext context)
{
this.Context = context;
}
}
public interface ISession
{
HttpContext Context { get; set; }
}
public HomeController(ISession session)
{
_session = session;
}
I think in order to test the controller I have mock the HttpContext first and then pass that object into the the construtor of the mocked ISession.
I have this so far
[Test]
public void index_returns_view()
{
//arrange
var mockHttpContext = new Mock<HttpContext>();
var mockContext = new Mock<ISession>(mockHttpContext);
var c = new HomeController(mockContext.Object);
//act
var v = c.Index() as ViewResult;
//assert
Assert.AreEqual(v.ViewName, "Index", "Index View name incorrect");
}
which builds but nunit returns the following error when the test is run
System.NotSupportedException : Type to mock must be an interface or an abstract or non-sealed class.
Thanks for all help.

Have your session take a HttpContextBase in the constructor and use that as the type of the property.
You should still be able to pass a concrete HttpContext the the session in production code.
public class SessionService : ISession
{
public HttpContextBase Context { get; set; }
public SessionService(HttpContextBase context)
{
this.Context = context;
}
}
Then fix your unit test by passing "mockHttpContext.Object" to the session constructor and that it mocks the HttpContextBase.
[Test]
public void index_returns_view()
{
//arrange
var mockHttpContext = new Mock<HttpContextBase>();
var mockContext = new Mock<ISession>(mockHttpContext.Object);
var c = new HomeController(mockContext.Object);
//act
var v = c.Index() as ViewResult;
//assert
Assert.AreEqual(v.ViewName, "Index", "Index View name incorrect");
}