diff --git a/acme/acme/challenges_test.py b/acme/acme/challenges_test.py
index 0fc8fcef7..ac94619b5 100644
--- a/acme/acme/challenges_test.py
+++ b/acme/acme/challenges_test.py
@@ -135,9 +135,8 @@ class DNS01Test(unittest.TestCase):
 
     def setUp(self):
         from acme.challenges import DNS01
-        self.msg = DNS01(
-            token=jose.decode_b64jose(
-                'evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ+PCt92wr+oA'))
+        self.msg = DNS01(token=jose.decode_b64jose(
+            'evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ+PCt92wr+oA'))
         self.jmsg = {
             'type': 'dns-01',
             'token': 'evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA',
diff --git a/acme/setup.py b/acme/setup.py
index e4a525605..3cb69ce9e 100644
--- a/acme/setup.py
+++ b/acme/setup.py
@@ -35,7 +35,7 @@ if sys.version_info < (2, 7, 9):
     install_requires.append('ndg-httpsclient')
     install_requires.append('pyasn1')
 
-dev_extras = [
+dns_extras = [
     'dnspython',
 ]
 
@@ -46,7 +46,6 @@ docs_extras = [
 ]
 
 testing_extras = [
-    'dnspython',
     'nose',
     'tox',
 ]
@@ -79,7 +78,7 @@ setup(
     include_package_data=True,
     install_requires=install_requires,
     extras_require={
-        'dev': dev_extras,
+        'dns': dns_extras,
         'docs': docs_extras,
         'testing': testing_extras,
     },
diff --git a/tox.ini b/tox.ini
index 1abe1cf39..98e185cfa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -33,23 +33,23 @@ setenv =
 
 [testenv:py33]
 commands =
-    pip install -e acme[testing]
+    pip install -e acme[dev,testing]
     nosetests -v acme
 
 [testenv:py34]
 commands =
-    pip install -e acme[testing]
+    pip install -e acme[dev,testing]
     nosetests -v acme
 
 [testenv:py35]
 commands =
-    pip install -e acme[testing]
+    pip install -e acme[dev,testing]
     nosetests -v acme
 
 [testenv:cover]
 basepython = python2.7
 commands =
-    pip install -e acme -e .[testing] -e letsencrypt-apache -e letsencrypt-nginx -e letshelp-letsencrypt
+    pip install -e acme[dns] -e .[testing] -e letsencrypt-apache -e letsencrypt-nginx -e letshelp-letsencrypt
     ./tox.cover.sh
 
 [testenv:lint]
@@ -59,7 +59,7 @@ basepython = python2.7
 # duplicate code checking; if one of the commands fails, others will
 # continue, but tox return code will reflect previous error
 commands =
-    pip install -e acme -e .[dev] -e letsencrypt-apache -e letsencrypt-nginx -e letsencrypt-compatibility-test -e letshelp-letsencrypt
+    pip install -e acme -e .[dns,dev] -e letsencrypt-apache -e letsencrypt-nginx -e letsencrypt-compatibility-test -e letshelp-letsencrypt
     ./pep8.travis.sh
     pylint --rcfile=.pylintrc letsencrypt
     pylint --rcfile=.pylintrc acme/acme