Fixed #25925 -- Forced LANG=C for test_msgfmt_error_including_non_ascii.

tests/i18n/test_compilation.py

@@ -6,6 +6,7 @@ import os
 import shutil
 import stat
 import unittest
+from subprocess import Popen
 
 from django.core.management import (
     CommandError, call_command, execute_from_command_line,
@@ -13,7 +14,7 @@ from django.core.management import (
 from django.core.management.commands.makemessages import \
     Command as MakeMessagesCommand
 from django.core.management.utils import find_command
-from django.test import SimpleTestCase, override_settings
+from django.test import SimpleTestCase, mock, override_settings
 from django.test.utils import captured_stderr, captured_stdout
 from django.utils import six, translation
 from django.utils._os import upath
@@ -164,6 +165,10 @@ class CompilationErrorHandling(MessageCompilationTests):
         with self.assertRaises(CommandError):
             call_command('compilemessages', locale=['ja'], verbosity=0)
 
+    # We will check the output of msgfmt, so we need to make sure its output
+    # is unaffected by the current locale.
+    @mock.patch('django.core.management.utils.Popen',
+        lambda *args, **kwargs: Popen(*args, env={'LANG': 'C'}, **kwargs))
     def test_msgfmt_error_including_non_ascii(self):
         # po file contains invalid msgstr content (triggers non-ascii error content).
         mo_file = 'locale/ko/LC_MESSAGES/django.mo'