def test_etagMatched(self):
        """
        If a request is made with an I{If-None-Match} ETag which does match the
        current ETag of the requested resource, a 304 response is returned along
        with an empty response body.
        """
        for line in [b"GET / HTTP/1.1", b"If-None-Match: MatchingTag", b""]:
            self.channel.dataReceived(line + b'\r\n')
        result = self.transport.getvalue()
        self.assertEqual(httpHeader(result, b"ETag"), b"MatchingTag")
        self.assertEqual(httpCode(result), http.NOT_MODIFIED)
        self.assertEqual(httpBody(result), b"")

        If a request is made with an I{If-None-Match} ETag which does match the
        current ETag of the requested resource, a 304 response is returned along
        with an empty response body.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_web.py