def test_proxy_buffering_headers_off(self):
        # This is the default, but we patch it anyway to make sure we're
        # testing the right thing should the default change.
        self.patch(StreamResourceMixin, 'proxy_buffering', False)
        receiver, received_messages = yield self.pull_message()
        headers = receiver._response.headers
        self.assertEqual(headers.getRawHeaders('x-accel-buffering'), ['no'])