I have created a patch for this for Python 3.1 and included an update to the unit tests.  The tests were never checking for a relative path and if they did would pas it even when it would have failed due to liberal use of os.path.abspath()

The test fix is probably not as clean as it could be by I did not want to severely alter its state.  The change to tempfile.mkdtemp() was clear and followed the current method tempfile.mkstemp() uses.