Change the PyUnit-based tests to use the test_main() approach.  This
allows using the tests with unittest.py as a script.  The tests will
still run when run as a script themselves.
diff --git a/Lib/test/test_rfc822.py b/Lib/test/test_rfc822.py
index 4040cdb..ab1746b 100644
--- a/Lib/test/test_rfc822.py
+++ b/Lib/test/test_rfc822.py
@@ -177,4 +177,10 @@
         self.check('To: User J. Person <person@dom.ain>\n\n',
                    [('User J. Person', 'person@dom.ain')])
 
-test_support.run_unittest(MessageTestCase)
+
+def test_main():
+    test_support.run_unittest(MessageTestCase)
+
+
+if __name__ == "__main__":
+    test_main()