language: node_js
node_js:
- '4'
script:
- yarn build
- yarn test

language: node_js
node_js:
- '4'

cache: yarn

script:
- yarn build
- yarn test

Optimize build by caching '~/.yarn-cache' directory
Optimize build by caching '~/.yarn-cache' directory

Reference:
  https://blog.travis-ci.com/2016-11-21-travis-ci-now-supports-yarn
