Tox tests detect downstream deps errors.

tox.ini

@@ -10,13 +10,14 @@ envlist = py27,cover,lint
 
 [testenv]
 commands =
-    pip install -r requirements.txt -e acme -e .[testing] -e letsencrypt-apache -e letsencrypt-nginx -e letshelp-letsencrypt
-    # -q does not suppress errors
-    python setup.py test -q
-    python setup.py test -q -s acme
-    python setup.py test -q -s letsencrypt_apache
-    python setup.py test -q -s letsencrypt_nginx
-    python setup.py test -q -s letshelp_letsencrypt
+    pip install -e acme[testing]
+    nosetests acme
+    pip install -r requirements.txt -e .[testing]
+    nosetests letsencrypt
+    pip install letsencrypt-apache
+    nosetests letsencrypt_apache
+    pip install letsencrypt-nginx
+    nosetests letsencrypt_nginx
 
 setenv =
     PYTHONPATH = {toxinidir}