Moq how to test BusinessLayer - moq

Question

I have problem with the Unit Test my Module from Business Layer.
I'm using Moq.
my Module from DL :
namespace EF.BusinessLayer.Modules
{
public class UserModule : IUserModule
{
public User AddUser(User user)
{
using (IUnitOfWork uow = IoC.Resolve<IUnitOfWork>())
{
uow.Add(user);
uow.SaveChanges();
return uow.Queryable<User>().Where(x => x.Username == user.Username).FirstOrDefault();
}
}
}
}
I'm trying to write a test, with which I can test if my entity was added properly.
[TestMethod]
public void AddUserTestMethod()
{
User user = new User()
{
FirstName = "Criss",
LastName = "Johnson",
Username = "CJ",
Email = "email#cj.com"
};
var mockContext = new Mock<IUserModule>();
mockContext.Setup<User>(x => x.AddUser(user)).Callback<User>((c) => User = c);
var result = mockContext.Object.AddUser(user);
}
but results = null.
What I'm doing wrong ?

Answer 1

Lets understand what is your system under test (SUT). From your description, I think it's UserModule.
Note that UserModule depends on IUnitOfWork, which you have very rightly dependency injected using an IoC container.
One of the key things of unit testing is to test the SUT in isolation. Which means for testing the business logic under UserModule, you should be mocking the IUnitOfWork. That's the problem I see with your test. It mocks the UserModule itself.
I suggest you to register the mocked IUnitOfWork in your IoC container before calling the "AddUser" method of UserModule.
[TestMethod]
public void AddUserTestMethod()
{
/*given*/
User expectedUser = new User()
{
FirstName = "Criss",
LastName = "Johnson",
Username = "CJ",
Email = "email#cj.com"
};
var users = new List<User>();
users.Add(expectedUser);
//mock IUnitWork
var mockUnitOfWork= new Mock<IUnitOfWork>();
mockUnitOfWork.Setup(x => x.Add(user));
mockUnitOfWork.Setup(x => x.SaveChanges());
//This may not work as is, could need modification
mockUnitOfWork.Setup(x => x.Queryable<User>()).Returns(users);
//Register mocked unit of work in IoC container
IoC.Register<IUnitOfWork>(mockUnitOfWork.Object);
//Instantiate SUT
var userModule = new UserModule();
/*when*/
var result = userModule.AddUser(user);
/*then*/
//Assert here
}