hive-forge: pr create --draft: extract draft_warning so the warning decision is tested

hive-forge/src/verbs/pr_create.rs

@@ -89,8 +89,8 @@ pub struct Args {
 /// token missing/invalid), an unresolved `--label` name, and any I/O
 /// error from writing the PR URL to stdout.
 pub fn run(client: &Client, args: Args) -> Result<()> {
-    if args.draft {
+    if let Some(w) = draft_warning(&args) {
-        eprintln!("{DRAFT_WARNING}");
+        eprintln!("{w}");
     }
     let body = body::resolve(args.body.as_deref(), args.body_file.as_deref())?.unwrap_or_default();
     if args.agit {
@@ -387,6 +387,10 @@ fn remote_content(line: &str) -> Option<&str> {
 
 const DRAFT_WARNING: &str = "warning: --draft is not supported by this forge; opening a normal PR";
 
+fn draft_warning(args: &Args) -> Option<&'static str> {
+    args.draft.then_some(DRAFT_WARNING)
+}
+
 fn is_remote_line(line: &str) -> bool {
     remote_content(line).is_some()
 }
@@ -401,17 +405,24 @@ fn is_pr_hint_opener(line: &str) -> bool {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use clap::Parser;
+
+    #[derive(clap::Parser)]
+    struct Cli {
+        #[command(flatten)]
+        args: Args,
+    }
 
     #[test]
-    fn draft_flag_parses() {
+    fn draft_flag_yields_warning() {
-        #[derive(clap::Parser)]
-        struct Cli {
-            #[command(flatten)]
-            args: Args,
-        }
-        use clap::Parser;
         let cli = Cli::parse_from(["x", "--title", "t", "--head", "h", "--draft"]);
-        assert!(cli.args.draft);
+        assert_eq!(draft_warning(&cli.args), Some(DRAFT_WARNING));
+    }
+
+    #[test]
+    fn no_draft_flag_yields_no_warning() {
+        let cli = Cli::parse_from(["x", "--title", "t", "--head", "h"]);
+        assert_eq!(draft_warning(&cli.args), None);
     }
 
     #[test]