如何在Entity Framework中模拟ObjectContext或ObjectQuery <T>？

public class MyDbContext : DbContext
{
    public MyDbContext() : base("name=MyConnectionString")
    {
    }

    public DbSet<Entity> Entities { get; set; }
}

public class MyDbContext : DbContext
{
    public MyDbContext() : base("name=MyConnectionString")
    {
    }

    public DbSet<Entity> Entities { get; set; }
}

using (var context = new MyDbContext())
{
    var query = from e in context.Entities
                where e.Property == "value"
                select e;

    var result = query.ToList();
}

using (var context = new MyDbContext())
{
    var entity = new Entity { Property = "value" };
    context.Entities.Add(entity);
    context.SaveChanges();
}