Configure help subcommand to print long form

[pwinckles]

Please complete the following tasks

I have searched the discussions
I have searched the existing issues

Describe your use case

The help subcommand prints the short help form, and I would like to configure it to print the long form instead.

The long form is more inline with my expectations of what the help subcommand should return. For example, compare the output of git help init, git init -h, and git init --help. At least on my system, the subcommand produces the long form; not the short form.

Describe the solution you'd like

Ideally this would be configurable via AppSettings.

Alternatives, if applicable

No response

Additional Context

No response

[reaganmcf]

I would like to work on this 😄

[reaganmcf]

I have made a little bit of progress on this (added the setting and started integration tests). However, I am wondering how I would go about writing integration tests for this. Reading over the code base, I found utils::compare_output() but that seems to be for errors.

(I am going to reformat and run clippy before I send the PR, so ignore that for now)

Here is an example of one of my tests, what is the best way to do this?

#[test]
fn subcommand_help_shows_long_form_with_setting_using_before_help() {
    let m = App::new("myprog")
        .setting(AppSettings::SubcommandHelpShowsLongForm)
        .subcommand(App::new("test")
            .before_help("short form help message")
            .before_long_help("long form help message"));
    assert!(utils::compare_output(
        m,
        "help test",
        SUBCOMMAND_HELP_LONG_FORM_USING_BEFORE_HELP,
        false)
    );
}

[ldm0]

@reaganmcf compare_output() is not only for errors. It can be used for both stdout and stderr. There is nothing wrong with you test.

[reaganmcf]

@ldm0 Currently the test above is pacnicking. Here is is the output:

---- subcommand_help_shows_long_form_with_setting_using_before_help stdout ----
thread 'subcommand_help_shows_long_form_with_setting_using_before_help' panicked at 
'called `Result::unwrap_err()` on an `Ok`  value: ArgMatches { args: {}, subcommand: Some(SubCommand { id: test, name: "test", matches: ArgMatches { args: {}, subcommand: None } }) }', 
tests/utils.rs:36:19

[ldm0]

@reaganmcf Hmm, check this?:

    assert!(utils::compare_output(
        m,
        "myprog help test",
        SUBCOMMAND_HELP_LONG_FORM_USING_BEFORE_HELP,
        false)
    );