diff --git a/tox.ini b/tox.ini
index ba6428d..114911c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,11 +6,12 @@
 [tox]
 envlist = {py27,py33,py34,py35,py36,pypy}
 skip_missing_interpreters = True
+minversion = 2.4.0
 
 [testenv]
-skip_install = True
+usedevelop = True
+extras = dev
 deps =
-    --editable=.[dev]
     pyflakes >= 1.2.3
 commands =
     pyflakes setup.py src
@@ -28,7 +29,6 @@ commands =
 
 [testenv:coverage]
 deps =
-    --editable=.[dev]
     pyflakes >= 1.2.3
     coverage
 commands =