diff --git a/setup.py b/setup.py
index abd32c4..f167628 100644
--- a/setup.py
+++ b/setup.py
@@ -24,5 +24,10 @@ setup(
     install_requires = [
         'docopt >= 0.6.1',
         'pygments >= 1.6.0',
-    ]
+    ],
+    extras_require   = {
+        'dev': [
+            'mock == 2.0.0',
+        ]
+    }
 )