post_test.rb: add more metatag search tests.

test/factories/note.rb

@@ -1,6 +1,6 @@
 FactoryGirl.define do
   factory(:note) do
-    creator :factory => :user
+    creator
     post
     x 1
     y 1
@@ -8,7 +8,6 @@ FactoryGirl.define do
     height 1
     is_active true
     body {FFaker::Lorem.sentences.join(" ")}
-    updater_id :factory => :user
     updater_ip_addr "127.0.0.1"
   end
 end