def METHOD_NAME(self):
    """
    Client call itself establishes connection.
    """
    config = self.connection_config.copy()
    with open_as_connection(config) as client:
        assert client is not None
        assert client.is_connected()
        client.close()
        assert client.is_connected() is False
        if TestBaseClass.user is None and TestBaseClass.password is None:
            client.connect()
        else:
            client.connect(TestBaseClass.user, TestBaseClass.password)
        assert client.is_connected()