diff -r ddf15cd9be4a Lib/test/regrtest.py
--- a/Lib/test/regrtest.py	Thu Jul 26 18:12:07 2012 -0400
+++ b/Lib/test/regrtest.py	Sat Jul 28 00:09:27 2012 +0900
@@ -173,6 +173,7 @@
 import getopt
 import io
 import json
+import locale
 import logging
 import os
 import platform
@@ -992,7 +993,7 @@
                  'sys.warnoptions', 'threading._dangling',
                  'multiprocessing.process._dangling',
                  'sysconfig._CONFIG_VARS', 'sysconfig._INSTALL_SCHEMES',
-                 'support.TESTFN',
+                 'support.TESTFN', 'locale',
                 )
 
     def get_sys_argv(self):
@@ -1161,6 +1162,17 @@
             elif os.path.isdir(support.TESTFN):
                 shutil.rmtree(support.TESTFN)
 
+    _locale_categories = [locale.LC_COLLATE, locale.LC_CTYPE,
+        locale.LC_MONETARY, locale.LC_NUMERIC, locale.LC_TIME]
+    if hasattr(locale, 'LC_MESSAGES'):
+        _locale_categories.append(locale.LC_MESSAGES)
+
+    def get_locale(self):
+        return [locale.getlocale(cat) for cat in self._locale_categories]
+    def restore_locale(self, saved_value):
+        for cat, value in zip(self._locale_categories, saved_value):
+            locale.setlocale(cat, value)
+
     def resource_info(self):
         for name in self.resources:
             method_suffix = name.replace('.', '_')
diff -r ddf15cd9be4a Lib/test/test___all__.py
--- a/Lib/test/test___all__.py	Thu Jul 26 18:12:07 2012 -0400
+++ b/Lib/test/test___all__.py	Sat Jul 28 00:09:27 2012 +0900
@@ -69,13 +69,14 @@
 
         # rlcompleter needs special consideration; it import readline which
         # initializes GNU readline which calls setlocale(LC_CTYPE, "")... :-(
+        import locale
+        org_locale = locale.getlocale(locale.LC_CTYPE)
         try:
             import rlcompleter
-            import locale
         except ImportError:
             pass
         else:
-            locale.setlocale(locale.LC_CTYPE, 'C')
+            locale.setlocale(locale.LC_CTYPE, org_locale)
 
         ignored = []
         failed_imports = []
diff -r ddf15cd9be4a Lib/test/test_regrtest.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Lib/test/test_regrtest.py	Sat Jul 28 00:09:27 2012 +0900
@@ -0,0 +1,38 @@
+from test.support import run_unittest, verbose
+import locale, unittest
+import test.test_locale
+from test.regrtest import saved_test_environment
+
+class TestSavedTestEnvironment(unittest.TestCase):
+    """Tests for regrtest.saved_test_environment"""
+
+    def test_locale_not_changed(self):
+        org = locale.setlocale(locale.LC_ALL)
+        try:
+            with saved_test_environment('dummytest', quiet=True) as env:
+                pass
+            self.assertFalse(env.changed)
+        finally:
+            locale.setlocale(locale.LC_ALL, org)
+
+    def test_locale_changed(self):
+        org = locale.setlocale(locale.LC_ALL)
+        try:
+            with saved_test_environment('dummytest', quiet=True) as env:
+                locale.setlocale(locale.LC_ALL, test.test_locale.enUS_locale)
+            self.assertTrue(env.changed)
+        finally:
+            locale.setlocale(locale.LC_ALL, org)
+
+def test_main():
+    # SkipTest can't be raised inside unittests, handle it manually instead
+    try:
+        test.test_locale.get_enUS_locale()
+    except unittest.SkipTest as e:
+        if verbose:
+            print("Some tests will be disabled: %s" % e)
+    else:
+        run_unittest(TestSavedTestEnvironment)
+
+if __name__ == '__main__':
+    test_main()