Fred wasn't kidding -- there really are docs for the locale module <wink>.

Obtain the original locale in the documented way.  This way actually
works for me.

Restore the original locale at the end, instead of forcing to "C".

Move the locale fiddling into the test driver instead of doing it as a
side effect of merely importing the module.  I don't know why the test
is mucking with locale (and also added a comment saying so), but it
surely has no justification for doing that as an import side-effect.
Now whenever the locale-changing code executes, the locale-restoring code
will also get run.

Lib/test/test_logging.py

@@ -26,16 +26,9 @@ Copyright (C) 2001-2002 Vinay Sajip. All Rights Reserved.
 
 import select
 import os, sys, string, struct, types, cPickle, cStringIO
-import socket, threading, time, locale
+import socket, threading, time
 import logging, logging.handlers, logging.config
 
-try:
-    cur_locale = locale.setlocale(locale.LC_ALL, '')
-except (ValueError, locale.Error):
-    # this happens on a Solaris box which only supports "C" locale
-    # or a Mac OS X box which supports very little locale stuff at all
-    cur_locale = None
-
 BANNER = "-- %-10s %-6s ---------------------------------------------------\n"
 
 FINISH_UP = "Finish up, it's closing time. Messages should bear numbers 0 through 24."
@@ -407,7 +400,7 @@ def banner(nm, typ):
     sys.stdout.write(sep)
     sys.stdout.flush()
 
-def test_main():
+def test_main_inner():
     rootLogger = logging.getLogger("")
     rootLogger.setLevel(logging.DEBUG)
     hdlr = logging.StreamHandler(sys.stdout)
@@ -474,8 +467,24 @@ def test_main():
         banner("logrecv output", "end")
         sys.stdout.flush()
 
-    if cur_locale:
-        locale.setlocale(locale.LC_ALL, "C")
+def test_main():
+    import locale
+    # Set the locale to the platform-dependent default.  I have no idea
+    # why the test does this, but in any case we save the current locale
+    # first so we can restore it at the end.
+    try:
+        original_locale = locale.setlocale(locale.LC_ALL)
+        locale.setlocale(locale.LC_ALL, '')
+    except (ValueError, locale.Error):
+        # this happens on a Solaris box which only supports "C" locale
+        # or a Mac OS X box which supports very little locale stuff at all
+        original_locale = None
+
+    try:
+        test_main_inner()
+    finally:
+        if original_locale:
+            locale.setlocale(locale.LC_ALL, original_locale)
 
 if __name__ == "__main__":
     sys.stdout.write("test_logging\n")