Updated ReferenceField's to optionally store ObjectId strings.

This will become the default in 0.8 (MongoEngine/mongoengine#89)

tests/test_all_warnings.py

@@ -37,6 +37,28 @@ class TestWarnings(unittest.TestCase):
         self.assertEqual(FutureWarning, warning["category"])
         self.assertTrue("InheritedClass" in str(warning["message"]))
 
+    def test_dbref_reference_field_future_warning(self):
+
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self')
+
+        Person.drop_collection()
+
+        p1 = Person()
+        p1.parent = None
+        p1.save()
+
+        p2 = Person(name="Wilson Jr")
+        p2.parent = p1
+        p2.save(cascade=False)
+
+        self.assertEqual(len(self.warning_list), 1)
+        warning = self.warning_list[0]
+        self.assertEqual(FutureWarning, warning["category"])
+        self.assertTrue("ReferenceFields will default to using ObjectId"
+                        in str(warning["message"]))
+
     def test_document_save_cascade_future_warning(self):
 
         class Person(Document):

tests/test_dereference.py

@@ -64,6 +64,130 @@ class FieldTest(unittest.TestCase):
         User.drop_collection()
         Group.drop_collection()
 
+    def test_list_item_dereference_dref_false(self):
+        """Ensure that DBRef items in ListFields are dereferenced.
+        """
+        class User(Document):
+            name = StringField()
+
+        class Group(Document):
+            members = ListField(ReferenceField(User, dbref=False))
+
+        User.drop_collection()
+        Group.drop_collection()
+
+        for i in xrange(1, 51):
+            user = User(name='user %s' % i)
+            user.save()
+
+        group = Group(members=User.objects)
+        group.save()
+
+        with query_counter() as q:
+            self.assertEqual(q, 0)
+
+            group_obj = Group.objects.first()
+            self.assertEqual(q, 1)
+
+            [m for m in group_obj.members]
+            self.assertEqual(q, 2)
+
+        # Document select_related
+        with query_counter() as q:
+            self.assertEqual(q, 0)
+
+            group_obj = Group.objects.first().select_related()
+
+            self.assertEqual(q, 2)
+            [m for m in group_obj.members]
+            self.assertEqual(q, 2)
+
+        # Queryset select_related
+        with query_counter() as q:
+            self.assertEqual(q, 0)
+            group_objs = Group.objects.select_related()
+            self.assertEqual(q, 2)
+            for group_obj in group_objs:
+                [m for m in group_obj.members]
+                self.assertEqual(q, 2)
+
+        User.drop_collection()
+        Group.drop_collection()
+
+    def test_handle_old_style_references(self):
+        """Ensure that DBRef items in ListFields are dereferenced.
+        """
+        class User(Document):
+            name = StringField()
+
+        class Group(Document):
+            members = ListField(ReferenceField(User, dbref=True))
+
+        User.drop_collection()
+        Group.drop_collection()
+
+        for i in xrange(1, 26):
+            user = User(name='user %s' % i)
+            user.save()
+
+        group = Group(members=User.objects)
+        group.save()
+
+        group = Group._get_collection().find_one()
+
+        # Update the model to change the reference
+        class Group(Document):
+            members = ListField(ReferenceField(User, dbref=False))
+
+        group = Group.objects.first()
+        group.members.append(User(name="String!").save())
+        group.save()
+
+        group = Group.objects.first()
+        self.assertEqual(group.members[0].name, 'user 1')
+        self.assertEqual(group.members[-1].name, 'String!')
+
+    def test_migrate_references(self):
+        """Example of migrating ReferenceField storage
+        """
+
+        # Create some sample data
+        class User(Document):
+            name = StringField()
+
+        class Group(Document):
+            author = ReferenceField(User, dbref=True)
+            members = ListField(ReferenceField(User, dbref=True))
+
+        User.drop_collection()
+        Group.drop_collection()
+
+        user = User(name="Ross").save()
+        group = Group(author=user, members=[user]).save()
+
+        raw_data = Group._get_collection().find_one()
+        self.assertTrue(isinstance(raw_data['author'], DBRef))
+        self.assertTrue(isinstance(raw_data['members'][0], DBRef))
+
+        # Migrate the model definition
+        class Group(Document):
+            author = ReferenceField(User, dbref=False)
+            members = ListField(ReferenceField(User, dbref=False))
+
+        # Migrate the data
+        for g in Group.objects():
+            g.author = g.author
+            g.members = g.members
+            g.save()
+
+        group = Group.objects.first()
+        self.assertEqual(group.author, user)
+        self.assertEqual(group.members, [user])
+
+        raw_data = Group._get_collection().find_one()
+        self.assertTrue(isinstance(raw_data['author'], basestring))
+        self.assertTrue(isinstance(raw_data['members'][0], basestring))
+
     def test_recursive_reference(self):
         """Ensure that ReferenceFields can reference their own documents.
         """

tests/test_document.py

@@ -1729,7 +1729,7 @@ class DocumentTest(unittest.TestCase):
 
     def test_circular_reference_deltas_2(self):
 
-        class Person( Document ):
+        class Person(Document):
            name = StringField()
            owns = ListField( ReferenceField( 'Organization' ) )
            employer = ReferenceField( 'Organization' )

tests/test_fields.py

@@ -7,7 +7,7 @@ import tempfile
 
 from decimal import Decimal
 
-from bson import Binary
+from bson import Binary, DBRef
 import gridfs
 
 from nose.plugins.skip import SkipTest
@@ -1086,6 +1086,42 @@ class FieldTest(unittest.TestCase):
         User.drop_collection()
         BlogPost.drop_collection()
 
+    def test_dbref_reference_fields(self):
+
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self', dbref=True)
+
+        Person.drop_collection()
+
+        p1 = Person(name="John").save()
+        Person(name="Ross", parent=p1).save()
+
+        col = Person._get_collection()
+        data = col.find_one({'name': 'Ross'})
+        self.assertEqual(data['parent'], DBRef('person', p1.pk))
+
+        p = Person.objects.get(name="Ross")
+        self.assertEqual(p.parent, p1)
+
+    def test_str_reference_fields(self):
+
+        class Person(Document):
+            name = StringField()
+            parent = ReferenceField('self', dbref=False)
+
+        Person.drop_collection()
+
+        p1 = Person(name="John").save()
+        Person(name="Ross", parent=p1).save()
+
+        col = Person._get_collection()
+        data = col.find_one({'name': 'Ross'})
+        self.assertEqual(data['parent'], "%s" % p1.pk)
+
+        p = Person.objects.get(name="Ross")
+        self.assertEqual(p.parent, p1)
+
     def test_list_item_dereference(self):
         """Ensure that DBRef items in ListFields are dereferenced.
         """
@@ -1122,6 +1158,7 @@ class FieldTest(unittest.TestCase):
             boss = ReferenceField('self')
             friends = ListField(ReferenceField('self'))
 
+        Employee.drop_collection()
         bill = Employee(name='Bill Lumbergh')
         bill.save()
 
@@ -1245,7 +1282,41 @@ class FieldTest(unittest.TestCase):
 
         class BlogPost(Document):
             title = StringField()
-            author = ReferenceField(Member)
+            author = ReferenceField(Member, dbref=False)
+
+        Member.drop_collection()
+        BlogPost.drop_collection()
+
+        m1 = Member(user_num=1)
+        m1.save()
+        m2 = Member(user_num=2)
+        m2.save()
+
+        post1 = BlogPost(title='post 1', author=m1)
+        post1.save()
+
+        post2 = BlogPost(title='post 2', author=m2)
+        post2.save()
+
+        post = BlogPost.objects(author=m1).first()
+        self.assertEqual(post.id, post1.id)
+
+        post = BlogPost.objects(author=m2).first()
+        self.assertEqual(post.id, post2.id)
+
+        Member.drop_collection()
+        BlogPost.drop_collection()
+
+    def test_reference_query_conversion_dbref(self):
+        """Ensure that ReferenceFields can be queried using objects and values
+        of the type of the primary key of the referenced object.
+        """
+        class Member(Document):
+            user_num = IntField(primary_key=True)
+
+        class BlogPost(Document):
+            title = StringField()
+            author = ReferenceField(Member, dbref=True)
 
         Member.drop_collection()
         BlogPost.drop_collection()