diff --git a/setup.cfg b/setup.cfg
index 0533d74bc..03f08f8b5 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -41,6 +41,10 @@ dimensions =
     Pillow
 bash =
     argcomplete
+test =
+    pytest-cov
+    pytest-xdist
+    responses
 
 [bdist_wheel]
-universal=1
+universal = 1
diff --git a/tox.ini b/tox.ini
index 3894c0893..6afa8551b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,8 +10,7 @@ commands =
 passenv = TRAVIS
 # Also install optional dependencies for tests.
 deps =
-    pytest-xdist
-    pytest-cov
+    .[css,dimensions,test]
     pytest-travis-fold
     cssselect
     Pillow