def delete(self, doc):
        if doc.id is None:
            raise DatabaseException('Document does not have id')
        if doc.sid is None:
            try:
                rs = self.db.docs.remove({'id': doc.id}, safe=True)
                assert rs['n'] == 1
            except Exception as e:
                raise DatabaseException(e)
            return None
        doc.data = None
        return self.update(doc)
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))