improve development instructions
@@ -27,7 +27,7 @@ You'll need to install py.test in order to run the Requests' test suite::
$ source .venv/bin/activate
$ make
- $ py.test tests
+ $ python setup.py test
============================= test session starts ==============================
platform darwin -- Python 3.4.4, pytest-3.0.6, py-1.4.32, pluggy-0.4.0
...
