use os.path.realpath in test

Author: noamcohen97

Lib/test/test_tarfile.py

@@ -1684,14 +1684,14 @@ def test_missing_fileobj(self):
     @unittest.mock.patch('os.chmod')
     def test_deferred_directory_attributes_update(self, mock_chmod):
         # Regression test for gh-127987: setting attributes on arbitrary files
-        tempdir = os.path.join(TEMPDIR, 'test127987')
+        tempdir = os.path.realpath(os.path.join(TEMPDIR, 'test127987'))
         def mock_chmod_side_effect(path, mode, **kwargs):
             target_path = os.path.realpath(path)
             if os.path.commonpath([target_path, tempdir]) != tempdir:
-                raise Exception("should not try to chmod anything outside the destination", target_path)
+                raise Exception(f"tried to chmod {path!r} ({target_path!r}) which is outside the tree ({tempdir!r})")
         mock_chmod.side_effect = mock_chmod_side_effect
 
-        outside_tree_dir = os.path.join(TEMPDIR, 'outside_tree_dir')
+        outside_tree_dir = os.path.realpath(os.path.join(TEMPDIR, 'outside_tree_dir'))
         with ArchiveMaker() as arc:
             arc.add('x', symlink_to='.')
             arc.add('x', type=tarfile.DIRTYPE, mode='?rwsrwsrwt')