How can I add to $PATH with tox?
I think it should work if you modify your path in the manage.py file to include django-protractor directory, because the Django management command line uses manage.py.
I'm using tox to run protractor tests which will test an application which uses django+angularjs, there is a glue library (django-protractor) which makes this easier, except that it makes the call to protractor inside a django management command, and relies on $PATH to show it where protractor is. 
So if I set the $PATH properly before running tox, it works fine, but I'd rather not require all the devs to do that manually.