[tests] Enable TestCosmeticChangesISBN tests

Bug: T356737

Change-Id: Ifb2e73352fe1193db91e4413029d27d27f70665d
---
M tests/cosmetic_changes_tests.py
1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/tests/cosmetic_changes_tests.py b/tests/cosmetic_changes_tests.py
index 4cc48b3..251d38b 100755
--- a/tests/cosmetic_changes_tests.py
+++ b/tests/cosmetic_changes_tests.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 """Test cosmetic_changes module."""
 #
-# (C) Pywikibot team, 2015-2022
+# (C) Pywikibot team, 2015-2024
 #
 # Distributed under the terms of the MIT license.
 #
@@ -13,8 +13,7 @@
 from pywikibot import Page
 from pywikibot.cosmetic_changes import CANCEL, CosmeticChangesToolkit
 from pywikibot.site import NamespacesDict
-from pywikibot.tools import has_module
-from tests.aspects import TestCase
+from tests.aspects import TestCase, require_modules
 
 
 class TestCosmeticChanges(TestCase):
@@ -548,6 +547,7 @@
         # Once numbering fixes are enabled we can add tests.
 
 
+@require_modules('stdnum')
 class TestCosmeticChangesISBN(TestCosmeticChanges):
 
     """Test CosmeticChanges ISBN fix."""
@@ -561,13 +561,6 @@
     ISBN_INVALIDCHARERROR_RE = 'ISBN [0-9a-zA-Z]+ contains invalid characters'
     ISBN_INVALIDLENGTHERROR_RE = 'The number has an invalid length'
 
-    @classmethod
-    def setUpClass(cls):
-        """Skip tests if isbn libraries are missing."""
-        if not has_module('stdnum', version='1.18'):
-            raise unittest.SkipTest('python-stdnum is not available.')
-        super().setUpClass()
-
     def test_valid_isbn(self):
         """Test ISBN."""
         text = self.cct.fix_ISBN(' ISBN 097522980x ')

