// SERVER-6179: support for two $groups in sharded agg
(function() {

var s = new ShardingTest({ name: "aggregation_multiple_group", shards: 2, mongos: 1 });
s.stopBalancer();

s.adminCommand({ enablesharding:"test" });
s.ensurePrimaryShard('test', 'shard0001');
s.adminCommand({ shardcollection: "test.data", key:{ _id: 1 } });

var d = s.getDB( "test" );

// Insert _id values 0 - 99
var N = 100;

var bulkOp = d.data.initializeOrderedBulkOp();
for(var i = 0; i < N; ++i) {
    bulkOp.insert({ _id: i, i: i%10 });
}
bulkOp.execute();

// Split the data into 3 chunks
s.adminCommand( { split:"test.data", middle:{ _id:33 } } );
s.adminCommand( { split:"test.data", middle:{ _id:66 } } );

// Migrate the middle chunk to another shard
s.adminCommand({ movechunk: "test.data",
                 find: { _id: 50 },
                 to: s.getOther(s.getServer("test")).name });

// Check that we get results rather than an error
var result = d.data.aggregate({$group: {_id: '$_id', i: {$first: '$i'}}},
                              {$group: {_id: '$i', avg_id: {$avg: '$_id'}}},
                              {$sort: {_id: 1}}).toArray();
expected = [
    {
        "_id" : 0,
        "avg_id" : 45
    },
    {
        "_id" : 1,
        "avg_id" : 46
    },
    {
        "_id" : 2,
        "avg_id" : 47
    },
    {
        "_id" : 3,
        "avg_id" : 48
    },
    {
        "_id" : 4,
        "avg_id" : 49
    },
    {
        "_id" : 5,
        "avg_id" : 50
    },
    {
        "_id" : 6,
        "avg_id" : 51
    },
    {
        "_id" : 7,
        "avg_id" : 52
    },
    {
        "_id" : 8,
        "avg_id" : 53
    },
    {
        "_id" : 9,
        "avg_id" : 54
    }
];

assert.eq(result, expected);

s.stop();

})();