language: node_js
node_js:
  - '8'
  - '9'
  - '10'
before_script:
  - npm install
script: npm test

language: node_js
node_js:
  - '6'
  - '7'
  - '8'
  - '9'
  - '10'
before_script:
  - npm install
script: npm test

Use node >= 6 for builds
Use node >= 6 for builds
