config_magic.rs

/// just some api ideas

#[test]
fn config_loading() {
    let fs = MockFS::new()
        .file("/usr/local/etc/foo", "fancy = 10")
        .file("~/.config/foo", "fancy = 20")
        .file(".env", "LE_PREFIX_FANCY=30");

    #[derive(Default, Configure, StructOpt)]
    struct Args {
        fancy: i32,
    }

    let args = Args::config()
        .config_source(ConfigSource::toml().with_mock_fs(fs))
        .config_source(ConfigSource::dot_env("LE_PREFIX"))
        .config_source(ConfigSource::env("LE_PREFIX"));

    assert_eq!(args.clone().load(), Args { fancy: 30 });

    std::env::set_var("LE_PREFIX_FANCY", "40");
    assert_eq!(args.clone().load(), Args { fancy: 40 });

    let args = args.clone()
        .config_source(ConfigSource::structopt()
            .handle_help_and_version()
            .with_mock_args(&["--fancy=50"])
        );

    assert_eq!(args.clone().load(), Args { fancy: 50 });
}