From 10509c34d6ebcd50505d53e64b23c6d6c4df8a38 Mon Sep 17 00:00:00 2001
From: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Date: Thu, 6 Aug 2026 13:48:58 +0300
Subject: [PATCH] gh-155009: Fix argparse test on non-UTF-8 locales like
 Raspbian (GH-155227) (cherry picked from commit
 297eb1b7488a46c8b6c4d87caaf658463ca72059)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
---
 Lib/test/test_argparse.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index e376c44faa4ae9..740119a952f81b 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -7132,6 +7132,9 @@ def test_module_as_main_without_altering_argv(self):
         basename = 'module' + os_helper.FS_NONASCII
         modulename = f'{self.dirname}.{basename}'
         self.make_script(self.dirname, basename)
+        # The filesystem encoding may be non-UTF-8,
+        # but the runner runs in UTF-8 mode
+        modulename = os.fsencode(modulename).decode("utf-8", "surrogateescape")
         runner_source = textwrap.dedent(f'''\
             import runpy
             runpy._run_module_as_main({modulename!r}, alter_argv=False)