def test_KEXINIT_badKexAlg(self):
        """
        Test that the client raises a ConchError if it receives a
        KEXINIT message but doesn't have a key exchange algorithm that we
        understand.
        """
        self.proto.supportedKeyExchanges = [b'diffie-hellman-group24-sha1']
        data = self.transport.value().replace(b'group14', b'group24')
        self.assertRaises(ConchError, self.proto.dataReceived, data)

        Test that the client raises a ConchError if it receives a
        KEXINIT message but doesn't have a key exchange algorithm that we
        understand.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_transport.py