machine:
  node:
    version: v6.7.0
test:
  override:
    - nvm install v6.7.0
    - nvm alias default v6.7.0
    - npm test
    - nvm install v4.6.0
    - nvm alias default v4.6.0
    - npm test

machine:
  node:
    version: v7.0.0
test:
  override:
    - nvm install v7.0.0
    - nvm alias default v7.0.0
    - npm test
    - nvm install v6.9.1
    - nvm alias default v6.9.1
    - npm test
    - nvm install v4.6.0
    - nvm alias default v4.6.0
    - npm test
    - nvm install v4.3.2
    - nvm alias default v4.3.2
    - npm test

Add versions 7.0.0, 4.3.2, update version 6.7.0 to 6.9.1
Add versions 7.0.0, 4.3.2, update version 6.7.0 to 6.9.1
