use clap::Parser; #[derive(Parser)] #[clap(author, version, about, long_about = None)] struct Cli { /// Network port to use #[clap(parse(try_from_str))] port: usize, } fn main() { let cli = Cli::parse(); println!("PORT = {}", cli.port); } #[test] fn verify_app() { use clap::CommandFactory; Cli::command().debug_assert() }