feat: Return help message as String for Command

src/builder/command.rs

@@ -708,6 +708,54 @@ impl<'help> App<'help> {
         c.print()
     }
 
+    /// Returns the help message (`-h`).
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use clap::Command;
+    /// let mut cmd = Command::new("myprog");
+    /// let help: String = cmd.get_help();
+    /// print!("{}",help);
+    /// ```
+    pub fn get_help(&mut self) -> String {
+        self._build_self();
+        let color = self.get_color();
+
+        let mut c = Colorizer::new(Stream::Stdout, color);
+        let usage = Usage::new(self);
+        match Help::new(HelpWriter::Buffer(&mut c), self, &usage, false).write_help() {
+            Ok(_) => c.to_owned().to_string(),
+            Err(e) => {
+                panic!("{}", e.to_string())
+            }
+        }
+    }
+
+    /// Returns the long help message.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use clap::Command;
+    /// let mut cmd = Command::new("myprog");
+    /// let help: String = cmd.get_long_help();
+    /// print!("{}",help);
+    /// ```
+    pub fn get_long_help(&mut self) -> String {
+        self._build_self();
+        let color = self.get_color();
+
+        let mut c = Colorizer::new(Stream::Stdout, color);
+        let usage = Usage::new(self);
+        match Help::new(HelpWriter::Buffer(&mut c), self, &usage, true).write_help() {
+            Ok(_) => c.to_owned().to_string(),
+            Err(e) => {
+                panic!("{}", e.to_string())
+            }
+        }
+    }
+
     /// Prints the long help message (`--help`) to [`io::stdout()`].
     ///
     /// See also [`Command::print_help`].

tests/builder/help.rs

@@ -606,6 +606,33 @@ SUBCOMMANDS:
     sub     short about sub
 ";
 
+static SETUP_HELP_MESSAGE: &str = "test 1.3
+Kevin K.
+tests stuff
+
+USAGE:
+    test
+
+OPTIONS:
+    -h, --help       Print help information
+    -V, --version    Print version information
+";
+
+static SETUP_LONG_HELP_MESSAGE: &str = "test 1.3
+Kevin K.
+tests stuff
+
+USAGE:
+    test
+
+OPTIONS:
+    -h, --help
+            Print help information
+
+    -V, --version
+            Print version information
+";
+
 fn setup() -> Command<'static> {
     Command::new("test")
         .author("Kevin K.")
@@ -2896,3 +2923,17 @@ fn display_name_subcommand_explicit() {
         Some("child.display")
     );
 }
+
+#[test]
+fn get_help_as_string() {
+    let cmd = &mut setup();
+    let help = cmd.get_help();
+    assert_eq!(help, SETUP_HELP_MESSAGE);
+}
+
+#[test]
+fn get_long_help_as_string() {
+    let cmd = &mut setup();
+    let help = cmd.get_long_help();
+    assert_eq!(help, SETUP_LONG_HELP_MESSAGE);
+}