SortingOnMapReduce.cs

// -----------------------------------------------------------------------
//  <copyright file="SortingOnMapReduce.cs" company="Hibernating Rhinos LTD">
//      Copyright (c) Hibernating Rhinos LTD. All rights reserved.
//  </copyright>
// -----------------------------------------------------------------------
using System.Linq;
using Raven.Abstractions.Indexing;
using Raven.Tests.Common;
using Raven.Tests.Helpers;

using Xunit;

namespace Raven.Tests.MailingList
{
    public class SortingOnMapReduce : RavenTestBase
    {
        public class Tag
        {
            public string Name { get; set; }
        }

        public class TagWithCount
        {
            public string Name { get; set; }
            public long Count { get; set; }
        }

        [Fact]
        public void MapReduceSortingBug()
        {
            using (var ds = this.NewDocumentStore())
            {
                ds.DatabaseCommands.PutIndex("TagsCount",
                    new IndexDefinition
                    {
                        Map = "from tag in docs.Tags select new { tag.Name, Count = 1 }",
                        Reduce = "from result in results group " +
                                 "result by result.Name into g " +
                                 "select new { Name = g.Key, Count = g.Sum(x => x.Count) }",
                    });

                using (var s = ds.OpenSession())
                {
                    s.Store(new Tag { Name = "one" });
                    s.Store(new Tag { Name = "two" });
                    s.Store(new Tag { Name = "two" });
                    s.Store(new Tag { Name = "three" });
                    s.Store(new Tag { Name = "three" });
                    s.Store(new Tag { Name = "three" });
                    s.SaveChanges();

                    var results =
                        s.Query<TagWithCount>("TagsCount")
                         .Customize(c => c.WaitForNonStaleResults())
                         .OrderByDescending(x => x.Count)
                         .Take(1)
                         .ToList();

                    Assert.Equal("three", results.Single().Name);
                    Assert.Equal(3, results.Single().Count);
                }
            }
        }
    }
}