test: Add test of derive functionality

It was noticed that between clap-rs#4443 and clap-rs#4432, an issue in the behavior
was that the derive api handles tasks with values slightly differently
than the declarative api. Added a test to show parity between
declaritive and derive api.

clap_mangen/Cargo.toml

@@ -45,7 +45,7 @@ clap = { path = "../", version = "4.0.0", default-features = false, features = [
 
 [dev-dependencies]
 snapbox = { version = "0.4", features = ["diff"] }
-clap = { path = "../", version = "4.0.0", default-features = false, features = ["std", "help"] }
+clap = { path = "../", version = "4.0.0", default-features = false, features = ["std", "help", "derive"] }
 
 [features]
 default = []

clap_mangen/tests/common.rs

@@ -312,17 +312,3 @@ pub fn possible_values_command(name: &'static str) -> clap::Command {
                 ]),
         )
 }
-
-/// Checks to make sure boolean valued "Flag options" do not generate
-/// suggestions for a parameter. i.e:
-///     --boolean_flag=BOOLEAN_FLAG
-///
-/// This is both confusing and suggest erroneous behavior as clap will fail if you
-/// pass a value to a boolean flag
-pub fn flag_without_value(name: &'static str) -> clap::Command {
-    clap::Command::new(name).arg(
-        clap::Arg::new("is_bool")
-            .long("is_bool")
-            .action(clap::ArgAction::SetTrue),
-    )
-}

clap_mangen/tests/derive.rs

@@ -0,0 +1,14 @@
+use clap::Parser;
+
+/// Checks to make sure boolean valued "Flag options" do not generate
+/// suggestions for a parameter. i.e:
+///     --boolean_flag=BOOLEAN_FLAG
+///
+/// This is both confusing and suggest erroneous behavior as clap will fail if you
+/// pass a value to a boolean flag
+#[derive(Parser, Debug)]
+#[command(name = "my-app")]
+pub struct FlagWithoutValue {
+    #[clap(long)]
+    boolean_flag: bool,
+}

clap_mangen/tests/roff.rs

@@ -1,4 +1,7 @@
 mod common;
+mod derive;
+
+use clap::CommandFactory;
 
 #[test]
 fn basic() {
@@ -72,8 +75,7 @@ fn possible_values() {
 
 #[test]
 fn flag_without_value() {
-    let name = "my-app";
-    let cmd = common::flag_without_value(name);
+    let cmd = derive::FlagWithoutValue::command();
     common::assert_matches_path("tests/snapshots/flag_without_value.bash.roff", cmd);
 }
 

clap_mangen/tests/snapshots/flag_without_value.bash.roff

@@ -2,14 +2,17 @@
 .el .ds Aq '
 .TH my-app 1  "my-app " 
 .SH NAME
-my/-app
+my/-app /- Checks to make sure boolean valued "Flag options" do not generate suggestions for a parameter. i.e: /-/-boolean_flag=BOOLEAN_FLAG
 .SH SYNOPSIS
-/fBmy/-app/fR [/fB/-/-is_bool/fR] [/fB/-h/fR|/fB/-/-help/fR] 
+/fBmy/-app/fR [/fB/-/-boolean/-flag/fR] [/fB/-h/fR|/fB/-/-help/fR] 
 .SH DESCRIPTION
+Checks to make sure boolean valued "Flag options" do not generate suggestions for a parameter. i.e: /-/-boolean_flag=BOOLEAN_FLAG
+.PP
+This is both confusing and suggest erroneous behavior as clap will fail if you pass a value to a boolean flag
 .SH OPTIONS
 .TP
-/fB/-/-is_bool/fR
+/fB/-/-boolean/-flag/fR
 
 .TP
 /fB/-h/fR, /fB/-/-help/fR
-Print help information
+Print help information (use `/-h` for a summary)