t = db.mr_comments t.drop() t.insert( { foo : 1 } ) t.insert( { foo : 1 } ) t.insert( { foo : 2 } ) res = db.runCommand( { mapreduce : "mr_comments", map : "// This will fail\n\n // Emit some stuff\n emit(this.foo, 1)\n", reduce : function(key, values){ return Array.sum(values); }, out: "mr_comments_out" }); assert.eq( 3 , res.counts.emit ) res = db.runCommand( { mapreduce : "mr_comments", map : "// This will fail\nfunction(){\n // Emit some stuff\n emit(this.foo, 1)\n}\n", reduce : function(key, values){ return Array.sum(values); }, out: "mr_comments_out" }); assert.eq( 3 , res.counts.emit )