[MERGE] Convert non-ascii blackbox tests to use internals where appropriate

[Alexander Belchenko]

Alexander Belchenko has voted approve.
Status is now: Approved
Comment:
thank you for using osutils functions properly.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C1189964091.18952.2.camel%40lapbert%3E