Isolate.WhenCalled(() => fakeContext.Context.CreateObjectSet<User>)).WillReturnCollectionValuesOf(fakeUsers.AsQueryable());

public static IQueryable<T> Include<T>(this IQueryable<T> source, Expression<Func<T>> property)
{
    var objectQuery = source as ObjectQuery<T>;

    if (objectQuery != null)
    {
        var propertyPath = GetPropertyPath(property);
        return objectQuery.Include(propertyPath);
    }

    return source;
}

public interface IMyObjectQuery<T> : IOrderedQueryable<T>
{
    IMyObjectQuery<T> Include(string path);
}

public class MyObjectQuery<T> : IMyObjectQuery<T>
{
    private ObjectQuery<T> _query;

    public MyObjectQuery(ObjectQuery<T> query)
    {
        _query = query;
    }

    IMyObjectQuery<T> Include(string path)
    {
        //There is probably a better way to do this
        //but you get the idea
        return new MyObjectQuery(_query.Include(path));
    }

    //Implement IQueryable, IEnumerable...
}

public class MyRepository : IMyRespository
{
    ...
    public IMyObjectQuery<T> CreateQuery<T>()
    {
        return new MyObjectQuery(_context.CreateQuery<T>());
    }
    ...
}