Entity Framework: implementing interfaces for a unit test

Today I wanted to start unit testing a small asp.net MVC 3 Web (test) application to learn some new things.

But things got worse than I expected ...

Now I have read some threads about unit testing regarding Entity framework, and now I first want to implement interfaces for related entity framework classes so that I can implement an in memory database for my unit tests.

My codebase is from the ASP.NET MVC tutorial . I've read MSDN but it doesn't help me in my cases.

I want to show you my code. I use the repository pattern unit:

Unit of work:

public class SqlUnitOfWork : IUnitOfWork, IDisposable
{
    private SqlContext context = new SqlContext();
    private IGenericRepository<Message> messageRepository;
    private IGenericRepository<Receipt> receiptRepository;
    private IGenericRepository<Useraccount> useraccountRepository;
    private bool disposed = false;

    public IGenericRepository<Message> MessageRepository
    {
        get
        {
            if (this.messageRepository == null)
            {
                this.messageRepository = new SqlGenericRepository<Message>(context);
            }
            return messageRepository;
        }
    }

    public IGenericRepository<Receipt> ReceiptRepository
    {
        get
        {
            if (this.receiptRepository == null)
            {
                this.receiptRepository = new SqlGenericRepository<Receipt>(context);
            }
            return receiptRepository;
        }
    }

    public IGenericRepository<Useraccount> UseraccountRepository
    {
        get
        {
            if (this.useraccountRepository == null)
            {
                this.useraccountRepository = new SqlGenericRepository<Useraccount>(context);
            }
            return useraccountRepository;
        }
    }

    public SqlUnitOfWork()
    {
    }

    ~SqlUnitOfWork()
    {
    }

    public virtual void Dispose(bool disposing)
    {
        if (!this.disposed)
        {
            if (disposing)
            {
                context.Dispose();
            }
        }

        this.disposed = true;
    }

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    public void Save()
    {
        context.SaveChanges();
    }
}

      

        
        
        
      

    

This tool implements the interface that I created.

My shared repository for sql:

public class SqlGenericRepository<TEntity> : IGenericRepository<TEntity> where TEntity : class
{
    internal SqlContext context;
    internal DbSet<TEntity> dbSet;

    public SqlGenericRepository(SqlContext context)
    {
        this.context = context;
        this.dbSet = context.Set<TEntity>();
    }

    ~SqlGenericRepository()
    {
    }

    public virtual IEnumerable<TEntity> Get(Expression<Func<TEntity, bool>> filter = null, 
        Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null, string includeProperties = "")
    {
        IQueryable<TEntity> query = dbSet;

        if (filter != null)
        {
            query = query.Where(filter);
        }

        foreach (var includeProperty in includeProperties.Split
            (new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
        {
            query = query.Include(includeProperty);
        }

        if (orderBy != null)
        {
            return orderBy(query).ToList();
        }
        else
        {
            return query.ToList();
        }
    }

    public virtual TEntity GetByID(object id)
    {
        return dbSet.Find(id);
    }

    public virtual void Insert(TEntity entity)
    {
        dbSet.Add(entity);
    }


    public virtual void Delete(object id)
    {
        TEntity entityToDelete = dbSet.Find(id);
        Delete(entityToDelete);
    }

    public virtual void Delete(TEntity entityToDelete)
    {
        if (context.Entry(entityToDelete).State == EntityState.Detached)
        {
            dbSet.Attach(entityToDelete);
        }
        dbSet.Remove(entityToDelete);
    }

    public virtual void Update(TEntity entityToUpdate)
    {
        dbSet.Attach(entityToUpdate);
        context.Entry(entityToUpdate).State = EntityState.Modified;
    }
}

      

        
        
        
      

    

It implements the interface that I have programmed:

public interface IGenericRepository<TEntity> where TEntity : class
{
    IEnumerable<TEntity> Get(Expression<Func<TEntity, bool>> filter = null, Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null, string includeProperties = "");

    TEntity GetByID(object id);

    void Insert(TEntity entity);

    void Delete(object id);

    void Delete(TEntity entityToDelete);

    void Update(TEntity entityToUpdate);
}

      

        
        
        
      

    

Now I would like to implement "InMemoryGenericRepository" for my unit tests and then "InMemoryUnitOfWork". What does this "InMemoryGenericRepository" look like?

I think I would use a generic list inside this repository where all the data is stored:

IEnumerable<TEntity> List { get; set; }

      

        
        
        
      

    

But how can I adapt this method:

public virtual IEnumerable<TEntity> Get(Expression<Func<TEntity, bool>> filter = null, Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null, string includeProperties = "")
{
    IQueryable<TEntity> query = dbSet;

    if (filter != null)
    {
        query = query.Where(filter);
    }

    foreach (var includeProperty in includeProperties.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries))
    {
        query = query.Include(includeProperty);
    }

    if (orderBy != null)
    {
        return orderBy(query).ToList();
    }
    else
    {
        return query.ToList();
    }
}

      

        
        
        
      

    

so it works with mine

IEnumerable<TEntity> List { get; set; }

      

        
        
        
      

    

I hope you made it to the end of my question.