bug fix for RefferenceField.to_mongo when dbref=False

mongoengine/fields.py

@@ -777,7 +777,7 @@ class ReferenceField(BaseField):
     def to_mongo(self, document):
         if isinstance(document, DBRef):
             if not self.dbref:
-                return DBRef.id
+                return document.id
             return document
         elif not self.dbref and isinstance(document, basestring):
             return document

tests/test_fields.py

@@ -1105,6 +1105,15 @@ class FieldTest(unittest.TestCase):
         p = Person.objects.get(name="Ross")
         self.assertEqual(p.parent, p1)
         
+    def test_dbref_to_mongo(self):
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self', dbref=False)
+    
+        p1 = Person._from_son({'name':"Yakxxx", 'parent': "50a234ea469ac1eda42d347d"})
+        mongoed = p1.to_mongo()
+        self.assertIsInstance(mongoed['parent'], ObjectId)
+
     def test_objectid_reference_fields(self):
 
         class Person(Document):