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_os.py b/Lib/test/test_os.py
index 9cddb5f..3f26f2f 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -62,5 +62,9 @@
         self.check_tempfile(os.tmpnam())
 
 
+def test_main():
+    run_unittest(TemporaryFileTests)
 
-run_unittest(TemporaryFileTests)
+
+if __name__ == "__main__":
+    test_main()