Whitespace normalization.  Ugh, we really need to do this more often.
You might want to review this change as it's my first time.  Be gentle. :-)
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 185d9da..a9294c0 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -281,7 +281,7 @@
         from os.path import join
 
         # Build:
-        #     TESTFN/               
+        #     TESTFN/
         #       TEST1/              a file kid and two directory kids
         #         tmp1
         #         SUB1/             a file kid and a directory kid