def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def test_cache_middleware(self):
        req = Request.blank('/something', environ={'REQUEST_METHOD': 'GET'})
        resp = self.app(req.environ, start_response)
        self.assertTrue('swift.cache' in resp)
        self.assertTrue(isinstance(resp['swift.cache'], MemcacheRing))