def METHOD_NAME(self, handler_hp):
    # get hold of the read-write Snmp-object
    snmp_read_only_handler = handler_hp._get_read_write_handle()
    # replace set-method on Snmp-object with a mock-method
    # all set-methods return None
    snmp_read_only_handler.set = Mock(return_value=None)
    interface = Mock()
    interface.ifindex = 1
    assert (
        handler_hp.set_interface_description(interface, "punkt1") is None
    ), "setIfAlias failed"