From now on, the line
from __future__ import unicode_literals
should be contained in every single Python file lest we run into any more 2.x/3.x issues.
Going forward, we're likely to develop on 3.x only and would likely miss subtle bugs otherwise.
If the test was run before the YoutubeIE tests (for example by running
"nosetests -v test/test_compat.py test/test_download.py -m 'Youtube_1|compat_expand'"),
it wrote the signatures cache to the 'C:\Documents and Settings\тест\Application Data' folder.
It failed due to a problem in the cache code and the write_json_file function (fixed in f03e33b89a622af13fa5275c46b63aaa4814c499)