Cannot seem to moq EF CodeFirst 4.1.Help anyone?

Question

I have been given the task to evaluate codeFirst and possible to use for all our future projects. The evaluation is based on using codeFirst with an existing database.

Answer 1

When I started with repository and unit of work patterns I used the implementation similar to this (it is for ObjectContext API but converting it to DbContext API is simple). We used that implementation with MOQ and Unity without any problems. By the time implementations of repository and unit of work have evolve as well as the approach of injecting. Later on we found that whole this approach has serious pitfalls but that was alredy discussed in other questions I referenced here (I highly recommend you to go through these links).

It is very surprising that you are evaluating the EFv4.1 with high emphasis on mocking and unit testing and in the same time you defined service method which is not unit-testable (with mocking) at all. The main problem of you service method is that you are not passing repository/context as dependency and because of that you can't mock it. The only way to test your service and don't use the real repository is using some very advanced approach = replacing mocking and MOQ with detouring (for example Moles framework).

First what you must do is replacing your service code with:

public class StudentService : IStudentService
{
    private readonly IStudentRepository _studentRepository;

    public StudentService(IStudentRepository studentRepository)
    {
        _studentRepository = studentRepository;
    }

    public IEnumerable GetAll()
    {
         return _studentRepository.GetAll().ToList();
    }
}

Btw. this is absolutely useless code and example of silly layering which doesn't offer any useful functionality. Just wrapping the call to repository only shows that service is not needed at all as well as unit testing this method is not needed. The main point here is integration test for GetAll method.

Anyway if you want to unit thest such method with MOQ you will do:

[TestClass]
public class StudentsServiveTest
{
    private Mock> _repo;

    [TestInitialize]
    public void Init()
    {
        _repo = new Mock>();
        _repo.Setup(r => r.GetAll()).Returns(() => new Student[] 
            { 
                new Student { StudentId = 1, Name = "A", Surname = "B" },
                new Student { StudentId = 2, Name = "B", Surname = "C" }
            });
    }

    [TestMethod]
    public void ShouldReturnAllStudents()
    {
        var service = new StudentsService(_repo.Object);
        var data = service.GetAll();
        _repo.Verify(r => r.GetAll(), Times.Once());

        Assert.IsNotNull(data);
        Assert.AreEqual(2, data.Count);
    }
}