C#

Pawel Krakowiak wrote:

I thought you don't want to hit the database (or other external resources) while running your tests and that's the main reason to use mock objects

Pawel Krakowiak wrote:

My colleague told me that when I'm testing that method I should use the concrete class and actually hit the database, and that I should mock IUserRepository only when it's needed in other tests (which are not testing FetchByID() but need data from it). Is that the correct approach?

public class UserRepository : IUserRepository
{
    IUserDataContainer container;
    public UserRepository(IUserDataContainer container)
    {
         this.container = container;
    }

    public IUser FetchByID(int userID)
    {
        User user = null;

        // Do various checks.
        // Fetch data from DB and assign to the user variable.
        UserDTO dto = dataContainer.FetchUserFrom(userId);
        user = UserConverter.ConvertFrom(dto);
        return user;
    }
}

[Test]
public void CanFetchUserById()
{
    UserRepository repository = new UserRepository();
    IUser user = repository.FetchUserById(1);
    Assert.That(user != NULL);
    Assert.AreEqual(user.Id,1);
    Assert.AreEqual(user.Name,"Jim");
}

public IUser FetchByID(int userID)
{
    throw new NotImplementedException();
}

N a v a n e e t h wrote:

Are you using inbuilt testing tools in VS or tools like NUnit ?

public IUser FetchByID(int userID)
{
    IUser user =
        new UserController().FetchByID(userID).ExecuteTypedList<User>()[0];

    return user;
}

N a v a n e e t h wrote:

You are writing tests but it's not test driven, is it ?

namespace Example.Data
{
    public interface IUserProvider
    {
        UserDTO FetchByID(int userID);
    }

    public class UserProvider : IUserProvider
    {
        public UserDTO FetchByID(int userID)
        {
            UserDTO user =
                new UserController().FetchByID(userID).ExecuteTypedList<UserDTO>()[0];

            return user;
        }
    }
}

namespace Example.Services
{
    public interface IUserRepository
    {
        IUser FetchByID(int userID);
    }

    public class UserRepository
    {
        private _provider = null;

        public UserRepository(IUserProvider provider)
        {
            this._provider = provider;
        }

        public IUser FetchByID(int userID)
        {
            UserDTO dto = _provider.FetchByID(userID);
            User user = UserConverter.ConvertFrom(dto);
            return user;
        }
    }
}

namespace Example.Tests
{
    [TestClass]
    public UserRepositoryTest
    {
        [TestMethod]
        public void FetchByID_ReturnsUser()
        {
            // Mock provider interface, so that we don't access the DB.
            var provider = new Mock<IUserProvider>();

            // Set up expectations on the mocked object.
            provider.Expect(p => p.FetchByID(1)).Returns(new User("John", "Doe"));

            // Perform tests.
            IUserRepository rep = new UserRepository(provider); // dependency injection
            IUser user = rep.FetchByID(1);
            Assert.IsNotNull(user);
            Assert.IsEqual("John", user.FirstName);
            Assert.IsEqual("Doe", user.LastName);

            // Verify that all mocks were used properly.
            provider.VerifyAll();
        }
    }
}