diff --git a/jstests/group5.js b/jstests/group5.js
index 086c56f3c8f..3534fe5f030 100644
--- a/jstests/group5.js
+++ b/jstests/group5.js
@@ -2,6 +2,7 @@
 t = db.group5;
 t.drop();
 
+// each group has groupnum+1 5 users
 for ( var group=0; group<10; group++ ){
     for ( var i=0; i<5+group; i++ ){
         t.save( { group : "group" + group , user : i } )
@@ -13,16 +14,25 @@ function c( group ){
         { 
             key : { group : 1 } , 
             q : { group : "group" + group } ,
-            initial : { users : [] },
+            initial : { users : {} },
             reduce :  function(obj,prev){
-                prev.users.push( obj.user );
+                prev.users[obj.user] = true; // add this user to the hash
             },
             finalize : function(x){
-                x.users = x.users.length;
+                var count = 0;
+                for (var key in x.users){
+                    count++;
+                }
+
+                //replace user obj with count
+                //count add new field and keep users
+                x.users = count;
                 return x;
             }
-        });
+        })[0]; // returns array
 }
 
-assert.eq( 5 , c(0) , "g0" );
-assert.eq( 10 , c(5) , "g5" );
+assert.eq( "group0" , c(0).group , "g0" );
+assert.eq( 5 ,        c(0).users , "g0 a" );
+assert.eq( "group5" , c(5).group , "g5" );
+assert.eq( 10 ,       c(5).users , "g5 a" );