language: node_js
node_js:
  - "4"
  - "6"
  - "8"
  - "10"
matrix:
  include:
    - env: SINON=3 MOCHA=3
    - env: SINON=4 MOCHA=4
    - env: SINON=5 MOCHA=5
before_install:
  - npm install --save-dev sinon@${SINON} mocha@${MOCHA}