clap/tests/derive/groups.rs

use clap::Parser;

#[test]
fn test_safely_nest_parser() {
    #[derive(Parser, Debug, PartialEq)]
    struct Opt {
        #[command(flatten)]
        foo: Foo,
    }

    #[derive(Parser, Debug, PartialEq)]
    struct Foo {
        #[arg(long)]
        foo: bool,
    }

    assert_eq!(
        Opt {
            foo: Foo { foo: true }
        },
        Opt::try_parse_from(&["test", "--foo"]).unwrap()
    );
}