Add 'pip install tox' at install step.

be-hase · be-hase · commit e11a36685845 · 2016-10-14T16:24:12.000+09:00
diff --git a/.travis.yml b/.travis.yml
@@ -20,6 +20,6 @@ env:
     - env: TOXENV=py35-flake8-tests
 
 install:
-  - pip install
+  - pip install tox
 
 script: tox
