The way to realise data access
Your code seems really good, I would change the ITestingRepository methods to return IEnumerable&lt;&gt; instead of List&lt;&gt;. 

Also, I suggest you would add a method signature to your generic repository interface that would let you query your DbContext.

public interface IGenericRepository&lt;T&gt; where T : class
{
    T Get(int id);
    void Create(T entityToCreate);
    void Edit(T entityToEdit);
    void Delete(T entityToDelete);
    IEnumerable&lt;T&gt; Get(Expression&lt;Func&lt;T,bool&gt;&gt; whereClause)
}


Then you can use it this way 

//Class example, I don't know what Testing class is
public class Testing
{
    public string PropertyOne { get; set;}
    public string PropertyTwo { get; set;}
}

public class TestingRepository
{
    //Method implementation
    public IEnumerable&lt;Testing&gt; Get(Expression&lt;Func&lt;Testing,bool&gt;&gt; whereClause)
    {
        IQueryable&lt;Testing&gt; result = _entities.Testing;

        if(whereClause != null)
            return result.Where(whereClause);

        return result.ToList();
    }
}

public static void AMethod() //Just to show an example at work!
{
    List&lt;Testing&gt; testings = new TestingRepository().Get(x =&gt; x.PropertyOne == "Hello" &amp;&amp; x.PropertyTwo == "World").ToList();
}


Finally, you might want to implement a generic repository class that implements your interface (a public class GenericRepository&lt;T&gt; : IGenericRepository&lt;T&gt;, I won't write it down for you but you could check this http://www.codeproject.com/Articles/640294/Learning-MVC-Part-Generic-Repository-Pattern-in