undecipherable error regarding venv on first run

I've done the following

bzr branch bundletester
make
sudo python setup.py install
pip install --user blessings (seems to be a missing dependency)

now when i cd into a charm directory and execute bundletester, i receive the following traceback, making it appear that bundletester wants a virtualenv

Traceback (most recent call last):
  File "/usr/local/bin/bundletester", line 9, in <module>
    load_entry_point('bundletester==0.3.3', 'console_scripts', 'bundletester')()
  File "/usr/local/lib/python2.7/dist-packages/bundletester-0.3.3-py2.7.egg/bundletester/tester.py", line 71, in main
    [report.emit(result) for result in run()]
  File "/usr/local/lib/python2.7/dist-packages/bundletester-0.3.3-py2.7.egg/bundletester/runner.py", line 121, in __call__
    self.build()
  File "/usr/local/lib/python2.7/dist-packages/bundletester-0.3.3-py2.7.egg/bundletester/runner.py", line 105, in build
    vpath = os.path.join(self.directory, '.venv')
AttributeError: 'Runner' object has no attribute 'directory'

There is no bundle config in the tests directory - which may be the root cause.