RavenDB MultiMapReduce Sum not returning the correct value - mapreduce

Question

Sorry for this lengthy query, I decided to add the whole test so that it will be easier for even newbies to help me with this total brain-melt.
The using directives are:
using System.Collections.Generic;
using System.Linq;
using NUnit.Framework;
using Raven.Client;
using Raven.Client.Embedded;
using Raven.Client.Indexes;
Please leave feedback if I'm too lengthy, but what could possibly go wrong if I add a complete test?
[TestFixture]
public class ClicksByScoreAndCardTest
{
private IDocumentStore _documentStore;
[SetUp]
public void SetUp()
{
_documentStore = new EmbeddableDocumentStore {RunInMemory = true}.Initialize();
_documentStore.DatabaseCommands.DisableAllCaching();
IndexCreation.CreateIndexes(typeof (ClicksBySearchAndProductCode).Assembly, _documentStore);
}
[TearDown]
public void TearDown()
{
_documentStore.Dispose();
}
[Test]
public void ShouldCountTotalLeadsMatchingPreference()
{
var userFirst = new User {Id = "users/134"};
var userSecond = new User {Id = "users/135"};
var searchFirst = new Search(userFirst)
{
Id = "searches/24",
VisitId = "visits/63"
};
searchFirst.Result = new Result();
searchFirst.Result.Rows = new List<Row>(
new[]
{
new Row {ProductCode = "CreditCards/123", Score = 6},
new Row {ProductCode = "CreditCards/124", Score = 4}
});
var searchSecond = new Search(userSecond)
{
Id = "searches/25",
VisitId = "visits/64"
};
searchSecond.Result = new Result();
searchSecond.Result.Rows = new List<Row>(
new[]
{
new Row {ProductCode = "CreditCards/122", Score = 9},
new Row {ProductCode = "CreditCards/124", Score = 4}
});
var searches = new List<Search>
{
searchFirst,
searchSecond
};
var click = new Click
{
VisitId = "visits/64",
ProductCode = "CreditCards/122",
SearchId = "searches/25"
};
using (var session = _documentStore.OpenSession())
{
foreach (var search in searches)
{
session.Store(search);
}
session.Store(click);
session.SaveChanges();
}
IList<ClicksBySearchAndProductCode.MapReduceResult> clicksBySearchAndProductCode = null;
using (var session = _documentStore.OpenSession())
{
clicksBySearchAndProductCode = session.Query<ClicksBySearchAndProductCode.MapReduceResult>(ClicksBySearchAndProductCode.INDEX_NAME)
.Customize(x => x.WaitForNonStaleResults()).ToArray();
}
Assert.That(clicksBySearchAndProductCode.Count, Is.EqualTo(4));
var mapReduce = clicksBySearchAndProductCode
.First(x => x.SearchId.Equals("searches/25")
&& x.ProductCode.Equals("CreditCards/122"));
Assert.That(mapReduce.Clicks,
Is.EqualTo(1));
}
}
public class ClicksBySearchAndProductCode :
AbstractMultiMapIndexCreationTask
<ClicksBySearchAndProductCode.MapReduceResult>
{
public const string INDEX_NAME = "ClicksBySearchAndProductCode";
public override string IndexName
{
get { return INDEX_NAME; }
}
public class MapReduceResult
{
public string SearchId { get; set; }
public string ProductCode { get; set; }
public string Score { get; set; }
public int Clicks { get; set; }
}
public ClicksBySearchAndProductCode()
{
AddMap<Search>(
searches =>
from search in searches
from row in search.Result.Rows
select new
{
SearchId = search.Id,
ProductCode = row.ProductCode,
Score = row.Score.ToString(),
Clicks = 0
});
AddMap<Click>(
clicks =>
from click in clicks
select new
{
SearchId = click.SearchId,
ProductCode = click.ProductCode,
Score = (string)null,
Clicks = 1
});
Reduce =
results =>
from result in results
group result by
new { SearchId = result.SearchId, ProductCode = result.ProductCode }
into g
select
new
{
SearchId = g.Key.SearchId,
ProductCode = g.Key.ProductCode,
Score = g.First(x => x.Score != null).Score,
Clicks = g.Sum(x => x.Clicks)
};
}
}
public class User
{
public string Id { get; set; }
}
public class Search
{
public string Id { get; set; }
public string VisitId { get; set; }
public User User { get; set; }
private Result _result = new Result();
public Result Result
{
get { return _result; }
set { _result = value; }
}
public Search(User user)
{
User = user;
}
}
public class Result
{
private IList<Row> _rows = new List<Row>();
public IList<Row> Rows
{
get { return _rows; }
set { _rows = value; }
}
}
public class Row
{
public string ProductCode { get; set; }
public int Score { get; set; }
}
public class Click
{
public string VisitId { get; set; }
public string SearchId { get; set; }
public string ProductCode { get; set; }
}
My problem here is that I expect Count to be one in that specific test, but it just doesn't seem to add the Clicks in the Click map and the result is 0 clicks. I'm totally confused, and I'm sure that there is a really simple solution to my problem, but I just can't find it..
..hope there is a week-end warrior out there who can take me under his wings.

Answer 1

Yes, it was a brain-melt, for me non-trivial, but still. The proper reduce should look like this:
Reduce =
results =>
from result in results
group result by
new { SearchId = result.SearchId, ProductCode = result.ProductCode }
into g
select
new
{
SearchId = g.Key.SearchId,
ProductCode = g.Key.ProductCode,
Score = g.Select(x=>x.Score).FirstOrDefault(),
Clicks = g.Sum(x => x.Clicks)
};
Not all Maps had the Score set to a non-null-value, and therefore my original version had a problem with:
Score = g.First(x => x.Score != null).Score
Mental note, use:
Score = g.Select(x=>x.Score).FirstOrDefault()
Don't use:
Score = g.First(x => x.Score != null).Score