From 2c8f00410301d3a184e03cf012a0737533478be4 Mon Sep 17 00:00:00 2001
From: sib <sib@narf.local>
Date: Thu, 30 Sep 2010 02:53:44 -0300
Subject: [PATCH 1/2] added update operator for addToSet

---
 mongoengine/queryset.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mongoengine/queryset.py b/mongoengine/queryset.py
index 069ab113..4d0f113c 100644
--- a/mongoengine/queryset.py
+++ b/mongoengine/queryset.py
@@ -662,7 +662,7 @@ class QuerySet(object):
         """Transform an update spec from Django-style format to Mongo format.
         """
         operators = ['set', 'unset', 'inc', 'dec', 'push', 'push_all', 'pull',
-                     'pull_all']
+                     'pull_all', 'add_to_set']
 
         mongo_update = {}
         for key, value in update.items():
@@ -680,7 +680,9 @@ class QuerySet(object):
                     op = 'inc'
                     if value > 0:
                         value = -value
-
+                elif op == 'add_to_set':
+                    op = op.replace('_to_set', 'ToSet')
+                    
             if _doc_cls:
                 # Switch field names to proper names [set in Field(name='foo')]
                 fields = QuerySet._lookup_field(_doc_cls, parts)
@@ -688,7 +690,7 @@ class QuerySet(object):
 
                 # Convert value to proper value
                 field = fields[-1]
-                if op in (None, 'set', 'unset', 'push', 'pull'):
+                if op in (None, 'set', 'unset', 'push', 'pull', 'addToSet'):
                     value = field.prepare_query_value(op, value)
                 elif op in ('pushAll', 'pullAll'):
                     value = [field.prepare_query_value(op, v) for v in value]

From 72c7a010ff6d782d850c245deee1857f87b9a1f4 Mon Sep 17 00:00:00 2001
From: sib <sib@narf.local>
Date: Thu, 30 Sep 2010 03:05:15 -0300
Subject: [PATCH 2/2] added unit test for addToSet

---
 tests/queryset.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/queryset.py b/tests/queryset.py
index 51f92993..10825d07 100644
--- a/tests/queryset.py
+++ b/tests/queryset.py
@@ -664,6 +664,11 @@ class QuerySetTest(unittest.TestCase):
         post.reload()
         self.assertTrue('db' in post.tags and 'nosql' in post.tags)
 
+        BlogPost.objects.update_one(add_to_set__tags='unique')
+        BlogPost.objects.update_one(add_to_set__tags='unique')
+        post.reload()
+        self.assertEqual(post.tags.count('unique'), 1)
+        
         BlogPost.drop_collection()
 
     def test_update_pull(self):