def test_continuedHeaderCallback(self):
        """
        If a header is split over multiple lines, L{HTTPParser} calls
        C{headerReceived} with the entire value once it is received.
        """
        header, protocol = self._headerTestSetup()
        protocol.dataReceived(b'X-Foo: bar' + self.sep)
        protocol.dataReceived(b' baz' + self.sep)
        protocol.dataReceived(b'\tquux' + self.sep)
        protocol.dataReceived(self.sep)
        self.assertEqual(header, {b'X-Foo': b'bar baz\tquux'})
        self.assertEqual(protocol.state, BODY)

        If a header is split over multiple lines, L{HTTPParser} calls
        C{headerReceived} with the entire value once it is received.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_newclient.py