using System;

using System.Linq;

using System.Collections.Generic;

using System.Text;

​

public class Program

{

    class MockRepository : IRepository

    {

        IList<MyEntity> _myEntities;

        public MockRepository()

        {

            _myEntities = new List<MyEntity>()

            {

            new MyEntity

            {

            ID = 1, Title = "My Entity One"

            }

​

            , new MyEntity

            {

            ID = 2, Title = "My Entity Two"

            }

​

            , new MyEntity

            {

            ID = 3, Title = "My Entity Three"

            }

            }

​

            ;

        }

​

        public IEnumerable<MyEntity> Get()

        {

            return _myEntities;

        }

​

        public void Dispose()

        {

            _myEntities = null;

        }

    }

​

    public static void Main()

    {

        const string EXPECTED = "My Entity One";

        IMyService svc = new MyService(new MockRepository());

        var actual = svc.GetEntity(1);

        Console.Write("Expected: {0}  |  Actual: {1}  |  Test result: {2}", EXPECTED, actual.Title, EXPECTED.Equals(actual.Title));

        Console.WriteLine(" ==== {0}", Convert.ToBase64String(Encoding.UTF8.GetBytes("My Value")));

    }

}

​

​

public class MyEntity

{

    public int ID

    {

        get;

        set;

    }

​

    public string Title

    {

        get;

        set;

    }

}

​

public interface IMyService

{

    MyEntity GetEntity(int entityId);

    IEnumerable<MyEntity> GetAllEntities();

}

​

public sealed class MyService : IMyService

{

    IRepository _repository;

    public MyService(IRepository repository)

    {

        _repository = repository;

    }

​

    public MyEntity GetEntity(int entityId)

    {

        var entities = GetAllEntities();

        var entity = entities.SingleOrDefault(e => e.ID == entityId);

        if (entity == null)

        {

            entity = new MyEntity

            {

            ID = -1, Title = "New Entity"

            }

​

            ;

        }

​

        return entity;

    }

​

    public IEnumerable<MyEntity> GetAllEntities()

    {

        var entities = _repository.Get();

        //Some rules and logics here, like:

        entities = entities.Where(e => !string.IsNullOrEmpty(e.Title));

        return entities; // To broke the test: return new List<MyEntity>();

    }

}

​

public interface IRepository : IDisposable

{

    IEnumerable<MyEntity> Get();

}