newitem: fix itemadaptor inheritance

--HG--
extra : convert_revision : svn%3Ab85faa78-f9eb-468e-a121-7cced6da292c%40924

scrapy/trunk/scrapy/contrib_exp/newitem/adaptors.py

@@ -14,6 +14,11 @@ class ItemAdaptor(object):
     def _get_field_adaptors(self):
         fa = {}
         for field in self.item_instance._fields.keys():
+            try:
+                fa[field] = object.__getattribute__(self, field)
+            except AttributeError:
+                pass
+
             if self.__class__.__dict__.has_key(field):
                 fa[field] = self.__class__.__dict__[field]
         return fa

scrapy/trunk/scrapy/tests/test_itemadaptor.py

@@ -1,6 +1,27 @@
 
 import unittest
 from scrapy.contrib_exp.newitem.adaptors import adaptor, ItemAdaptor
+from scrapy.contrib_exp.newitem import Item, StringField
+
+
+class TestItem(Item):
+    name = StringField()
+    url = StringField()
+
+
+class ItemAdaptorTest(unittest.TestCase):
+
+    def test_inheritance(self):
+        class TestAdaptor(ItemAdaptor):
+            item_class = TestItem
+            name = lambda v, adaptor_args: v.title()
+
+        class ChildTestAdaptor(TestAdaptor):
+            url = lambda v, adaptor_args: v.lower()
+
+        ia = ChildTestAdaptor()
+        assert 'url' in ia._field_adaptors
+        assert 'name' in ia._field_adaptors
 
 
 class TreeadaptTest(unittest.TestCase):