Align the fetch-lyrics summary with fetch-artists via shared utils

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tools/tests/test_utils.py

@@ -0,0 +1,21 @@
+# Tools for A Feminist Audit of Pop Music.
+# Copyright 2026 imacat.  All rights reserved.
+# Authors:
+#   imacat@mail.imacat.idv.tw (imacat), 2026/8/4
+"""Unit tests for the shared utilities module."""
+import unittest
+
+from pop_fem_audit_tools import utils
+
+
+class TestUtils(unittest.TestCase):
+    """Test cases for the shared utilities."""
+
+    def test_format_duration_under_hour(self) -> None:
+        """Test the mm:ss format for a duration under one hour."""
+        self.assertEqual(utils.format_duration(205), "03:25")
+
+    def test_format_duration_over_hour(self) -> None:
+        """Test the h:mm:ss format once the duration reaches an
+        hour."""
+        self.assertEqual(utils.format_duration(6439), "1:47:19")