def test_responseHeadersMultiline(self):
        """
        The multi-line response headers are folded and added to the response
        object's C{headers} L{Headers} instance.
        """
        protocol = HTTPClientParser(
            Request(b'GET', b'/', _boringHeaders, None),
            lambda rest: None)
        protocol.makeConnection(StringTransport())
        protocol.dataReceived(b'HTTP/1.1 200 OK\r\n')
        protocol.dataReceived(b'X-Multiline: a\r\n')
        protocol.dataReceived(b'    b\r\n')
        protocol.dataReceived(b'\r\n')
        self.assertEqual(
            protocol.connHeaders,
            Headers({}))
        self.assertEqual(
            protocol.response.headers,
            Headers({b'x-multiline': [b'a    b']}))
        self.assertIdentical(protocol.response.length, UNKNOWN_LENGTH)

        The multi-line response headers are folded and added to the response
        object's C{headers} L{Headers} instance.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_newclient.py