'Make sure that older threads in the comments service without the pinned
field do not break serialization'

def test_pinned_missing(self):

    thread_data = self.make_cs_content({})
    del thread_data['pinned']
    self.register_get_thread_response(thread_data)
    serialized = self.serialize(thread_data)
    self.assertEqual(serialized['pinned'], False)
