merge commments and likes from FB photo and photo post objects

yet more work to handle FB's awful data model for photo posts. kind of for #189...kind of.

facebook.py

@@ -164,23 +164,33 @@ def get_activities_response(self, **kwargs):
     # id. the post's object_id field points to the photo's id. de-dupe by
     # switching the post to use the fb_object_id when it's provided.
     activities = resp.setdefault('items', [])
-    fb_ids = set()
+    activities_by_fb_id = {}
     for activity in activities:
       obj = activity.get('object', {})
       fb_id = obj.get('fb_object_id')
       if not fb_id:
         continue
 
-      fb_ids.add(fb_id)
+      activities_by_fb_id[fb_id] = activity
       for x in activity, obj:
         parsed = util.parse_tag_uri(x.get('id', ''))
         if parsed:
           _, orig_id = parsed
           x['id'] = self.as_source.tag_uri(fb_id)
           x['url'] = x.get('url', '').replace(orig_id, fb_id)
 
-    activities += [self.as_source.post_to_activity(p) for p in photos
-                   if p.get('id') not in fb_ids]
+
+    for photo in photos:
+      photo_activity = self.as_source.post_to_activity(photo)
+      existing = activities_by_fb_id.get(photo.get('id'))
+      if existing:
+        existing['object'].setdefault('replies', {}).setdefault('items', []).extend(
+          photo_activity['object'].get('replies', {}).get('items', []))
+        existing['object'].setdefault('tags', []).extend(
+            [t for t in photo_activity['object'].get('tags', [])
+             if t.get('verb') == 'like'])
+      else:
+        activities.append(photo_activity)
 
     # add events
     activities += [self.as_source.event_to_activity(e, rsvps=r)

facebook_test.py

@@ -108,7 +108,13 @@ def test_get_activities_post_and_photo_duplicates(self):
       json.dumps({}))
     self.mox.ReplayAll()
 
-    self.assert_equals([self.post_activity], self.fb.get_activities())
+    got = self.fb.get_activities()
+    self.assertEquals(1, len(got))
+    obj = got[0]['object']
+    self.assertEquals('tag:facebook.com,2013:222', obj['id'])
+    self.assertEquals('https://facebook.com/212038/posts/222', obj['url'])
+    self.assertEquals(3, len(obj['replies']['items']))
+    self.assertEquals(3, len([t for t in obj['tags'] if t.get('verb') == 'like']))
 
   def test_revoked(self):
     self.expect_urlopen(