FIX TST Fix for #20996

Converting to string removed the windows compatible path.

Author: gaborkertesz

sklearn/utils/tests/test_cython_templating.py

@@ -11,10 +11,12 @@ def test_files_generated_by_templates_are_git_ignored():
 
     base_dir = pathlib.Path(sklearn.__file__).parent
     ignored_files = open(gitignore_file, "r").readlines()
-    ignored_files = list(map(lambda line: line.strip("\n"), ignored_files))
+    ignored_files = list(
+        map(lambda line: pathlib.Path(line.strip("\n")), ignored_files)
+    )
 
     for filename in base_dir.glob("**/*.tp"):
         filename = filename.relative_to(base_dir.parent)
         # From "path/to/template.p??.tp" to "path/to/template.p??"
         filename_wo_tempita_suffix = filename.with_suffix("")
-        assert str(filename_wo_tempita_suffix) in ignored_files
+        assert filename_wo_tempita_suffix in ignored_files