language: php

php:
  - 5.4
  - 5.5
  - 5.6
  - 7.0
  - 7.1
  - 7.2
  - 7.3
  - hhvm

before_script:
  - travis_retry composer self-update
  - travis_retry composer update --prefer-source --no-interaction --dev

script: phpunit