For ddt that has unicode data, dynamic test name generating will cause unicode decode error for Python3

[tonytan4ever]

https://github.com/testing-cabal/testtools/blob/master/testtools/run.py#L183, see stack trace below:

Traceback (most recent call last):
File "/usr/local/Cellar/python3/3.4.3_2/Frameworks/Python.framework/Versions/3.4/lib/python3.4/runpy.py", line 170, in _run_module_as_main
"main", mod_spec)
File "/usr/local/Cellar/python3/3.4.3_2/Frameworks/Python.framework/Versions/3.4/lib/python3.4/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/Users/tony7514/projects/Rackspace/cdn/.tox/py34/lib/python3.4/site-packages/subunit/run.py", line 149, in
main()
File "/Users/tony7514/projects/Rackspace/cdn/.tox/py34/lib/python3.4/site-packages/subunit/run.py", line 145, in main
stdout=stdout, exit=False)
File "/Users/tony7514/projects/Rackspace/cdn/.tox/py34/lib/python3.4/site-packages/testtools/run.py", line 183, in init
test_ids = set(line.strip().decode('utf-8') for line in lines)
File "/Users/tony7514/projects/Rackspace/cdn/.tox/py34/lib/python3.4/site-packages/testtools/run.py", line 183, in
test_ids = set(line.strip().decode('utf-8') for line in lines)