ln: Using unit test macros for ln and creating test cases for exception handling

src/uu/ln/locales/en-US.ftl

@@ -29,7 +29,6 @@ ln-error-missing-destination = missing destination file operand after {$operand}
 ln-error-extra-operand = extra operand {$operand}
   Try '{$program} --help' for more information.
 ln-error-could-not-update = Could not update {$target}: {$error}
-ln-error-cannot-stat = cannot stat {$path}: No such file or directory
 ln-error-will-not-overwrite = will not overwrite just-created '{$target}' with '{$source}'
 ln-prompt-replace = replace {$file}?
 ln-cannot-backup = cannot backup {$file}

src/uu/ln/locales/fr-FR.ftl

@@ -30,7 +30,6 @@ ln-error-missing-destination = opérande de fichier de destination manquant apr
 ln-error-extra-operand = opérande supplémentaire {$operand}
   Essayez « {$program} --help » pour plus d'informations.
 ln-error-could-not-update = Impossible de mettre à jour {$target} : {$error}
-ln-error-cannot-stat = impossible d'analyser {$path} : Aucun fichier ou répertoire de ce nom
 ln-error-will-not-overwrite = ne remplacera pas le fichier « {$target} » qui vient d'être créé par « {$source} »
 ln-prompt-replace = remplacer {$file} ?
 ln-cannot-backup = impossible de sauvegarder {$file}

src/uu/ln/src/ln.rs

@@ -101,8 +101,6 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         .map(PathBuf::from)
         .collect();
 
-    let symbolic = matches.get_flag(options::SYMBOLIC);
-
     let overwrite_mode = if matches.get_flag(options::FORCE) {
         OverwriteMode::Force
     } else if matches.get_flag(options::INTERACTIVE) {
@@ -114,15 +112,13 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let backup_mode = backup_control::determine_backup_mode(&matches)?;
     let backup_suffix = backup_control::determine_backup_suffix(&matches);
 
-    // When we have "-L" or "-L -P", false otherwise
-    let logical = matches.get_flag(options::LOGICAL);
-
     let settings = Settings {
         overwrite: overwrite_mode,
         backup: backup_mode,
         suffix: OsString::from(backup_suffix),
-        symbolic,
-        logical,
+        symbolic: matches.get_flag(options::SYMBOLIC),
+        // When we have "-L" or "-L -P", false otherwise
+        logical: matches.get_flag(options::LOGICAL),
         relative: matches.get_flag(options::RELATIVE),
         target_dir: matches
             .get_one::<OsString>(options::TARGET_DIRECTORY)
@@ -132,7 +128,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         verbose: matches.get_flag(options::VERBOSE),
     };
 
-    exec(&paths[..], &settings)
+    exec(&paths, &settings)
 }
 
 pub fn uu_app() -> Command {
@@ -295,8 +291,10 @@ fn link_files_in_dir(files: &[PathBuf], target_dir: &Path, settings: &Settings)
             && matches!(settings.overwrite, OverwriteMode::Force)
             && target_dir.is_symlink()
         {
-            // In that case, we don't want to do link resolution
-            // We need to clean the target
+            // We don't want to do link resolution, we need to clean the target.
+            // Unreachable on Unix: target_dir is a symlink to a directory here,
+            // so is_file() is always false.
+            #[cfg(windows)]
             if target_dir.is_file() {
                 if let Err(e) = fs::remove_file(target_dir) {
                     show_error!(
@@ -319,25 +317,15 @@ fn link_files_in_dir(files: &[PathBuf], target_dir: &Path, settings: &Settings)
             }
             target_dir.to_path_buf()
         } else {
-            match srcpath.as_os_str().to_str() {
-                Some(name) => {
-                    match Path::new(name).file_name() {
-                        Some(basename) => target_dir.join(basename),
-                        // This can be None only for "." or "..". Trying
-                        // to create a link with such name will fail with
-                        // EEXIST, which agrees with the behavior of GNU
-                        // coreutils.
-                        None => target_dir.join(name),
-                    }
-                }
-                None => {
-                    show_error!(
-                        "{}",
-                        translate!("ln-error-cannot-stat", "path" => srcpath.quote())
-                    );
-                    all_successful = false;
-                    continue;
-                }
+            // Use OsStr directly to handle non-UTF8 paths correctly
+            let name = srcpath.as_os_str();
+            match srcpath.file_name() {
+                Some(basename) => target_dir.join(basename),
+                // This can be None only for "." or "..". Trying
+                // to create a link with such name will fail with
+                // EEXIST, which agrees with the behavior of GNU
+                // coreutils.
+                None => target_dir.join(name),
             }
         };