feat: colour the help, and check the command definition

src/cli/ahab.rs

@@ -1,10 +1,12 @@
 use super::{Django, Link, Postgres};
+use clap::builder::styling::{AnsiColor, Effects, Styles};
 use clap::{Parser, Subcommand};
 use clap_complete::Shell;
 
 /// A program for interacting with various dockerized applications
 #[derive(Parser, Debug)]
-#[command(author, version, about, long_about=None)]
+#[command(version, about, long_about = None)]
+#[command(styles = help_styles())]
 pub struct Ahab {
     #[command(subcommand)]
     pub command: Commands,
@@ -43,3 +45,23 @@ pub enum Commands {
         shell: Shell,
     },
 }
+
+// clap styles headers bold by default but adds no colour
+fn help_styles() -> Styles {
+    Styles::styled()
+        .header(AnsiColor::Green.on_default() | Effects::BOLD)
+        .usage(AnsiColor::Green.on_default() | Effects::BOLD)
+        .literal(AnsiColor::Cyan.on_default() | Effects::BOLD)
+        .placeholder(AnsiColor::Cyan.on_default())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Ahab;
+    use clap::CommandFactory;
+
+    #[test]
+    fn the_command_is_well_formed() {
+        Ahab::command().debug_assert();
+    }
+}