def test_unencryptedConnectionWithoutPasswords(self):
        """
        If the L{SSHUserAuthServer} is not advertising passwords, then an
        unencrypted connection should not cause any warnings or exceptions.
        This is a white box test.
        """
        # create a Portal without password authentication
        portal = Portal(self.realm)
        portal.registerChecker(PrivateKeyChecker())

        # no encryption
        clearAuthServer = userauth.SSHUserAuthServer()
        clearAuthServer.transport = FakeTransport(portal)
        clearAuthServer.transport.isEncrypted = lambda x: False
        clearAuthServer.serviceStarted()
        clearAuthServer.serviceStopped()
        self.assertEqual(clearAuthServer.supportedAuthentications,
                          [b'publickey'])

        # only encrypt incoming (the direction the password is sent)
        halfAuthServer = userauth.SSHUserAuthServer()
        halfAuthServer.transport = FakeTransport(portal)
        halfAuthServer.transport.isEncrypted = lambda x: x == 'in'
        halfAuthServer.serviceStarted()
        halfAuthServer.serviceStopped()
        self.assertEqual(clearAuthServer.supportedAuthentications,
                          [b'publickey'])

        If the L{SSHUserAuthServer} is not advertising passwords, then an
        unencrypted connection should not cause any warnings or exceptions.
        This is a white box test.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_userauth.py