Issue #14135: Let's try this again.

Lib/test/regrtest.py

@@ -127,6 +127,7 @@ import builtins
 import faulthandler
 import io
 import json
+import locale
 import logging
 import os
 import platform
@@ -1061,7 +1062,7 @@ class saved_test_environment:
                  'sys.warnoptions', 'threading._dangling',
                  'multiprocessing.process._dangling',
                  'sysconfig._CONFIG_VARS', 'sysconfig._INSTALL_SCHEMES',
-                 'support.TESTFN',
+                 'support.TESTFN', 'locale',
                 )
 
     def get_sys_argv(self):
@@ -1230,6 +1231,19 @@ class saved_test_environment:
             elif os.path.isdir(support.TESTFN):
                 shutil.rmtree(support.TESTFN)
 
+    _lc = [getattr(locale, lc) for lc in dir(locale) if lc.startswith('LC_')]
+    def get_locale(self):
+        pairings = []
+        for lc in self._lc:
+            try:
+                pairings.append((lc, locale.getlocale(lc)))
+            except TypeError:
+                continue
+        return pairings
+    def restore_locale(self, saved):
+        for lc, setting in saved:
+            locale.setlocale(lc, setting)
+
     def resource_info(self):
         for name in self.resources:
             method_suffix = name.replace('.', '_')