Mocking service method for unit test

Question

I'm trying to test GetUserDetails from UserTest class. test user has data, but test always returns null for getUser . Do I write test correctly? Any suggestion how to use service method here in a rigth way

[TestClass]
public class UserTest
{
    IUserService _userService;

    [TestInitialize]
    public void Setup()
    {
        _userService = new Mock<IUserService>().Object; 
    }

    [TestMethod]
    public void getUserInfo()
    {
        var getUser = _userService.GetUserDetails("test"); //it's not null, user has data

        Assert.IsNotNull(getUser); //always null
    }
}

Answer 1

If you are testing GetUserDetails you should not mock the service it is part of.

Your test should look more like this:

[TestMethod]
public void TestGetUser()
{
    var mockLogger = new Mock<ILogger>(MockBehaviour.Strict);
    var mockRepo = new Mock<IMyRepo>(MockBehaviour.Strict);

    var beingTested = new UsersService(
        logger: mockLogger.Object
        userRepo: mockRepo.Object,
        ...);

    mockRepo.Setup( r => r.GetUserFromDb("test")).Returns( new UserDetails(...));

    var getUser = beingTested.GetUserDetails("test"); 

    Assert.IsNotNull(getUser);
}