def test_process_arguments(): parser = Mock() args = Namespace() args.sinks = [] args.jobs = None process_arguments(args, parser) parser.error.assert_called_with('at least one sink is required') args.sinks = [1, 2, 3] process_arguments(args, parser) assert args.jobs == 3 args.jobs = 1 process_arguments(args, parser) assert args.jobs == 1