Update .travis.yml

methane · methane · commit f8e62400a19b · 2014-04-15T17:52:45.000+09:00
diff --git a/.travis.yml b/.travis.yml
@@ -3,5 +3,5 @@ services:
 language: python
 python: 3.3
 before_script:
-    - "pip install --upgrade pip tox"
+    - "pip install --upgrade pip tox virtualenv"
 script: "tox"
