Using Yarn on Travis-CI

.travis.yml

language: node_js
node_js:
  - "6"
env:
  - CXX=g++-4.8
addons:
  apt:
    sources:
      - ubuntu-toolchain-r-test
    packages:
      - g++-4.8
before_install:
  - npm install -g yarn --cache-min 999999999
install:
  - yarn

Is it necessary for the env and addons stuff? What exactly are they needed for?

Exact same question as @balupton. g++ is required for building native deps. mostly 😕

For anyone looking into this now:

Using npm to install yarn has blown up everything. yarnpkg/yarn#2915

https://yarnpkg.com/en/docs/install-ci#travis-tab

Nowadays, Yarn comes preinstalled when using language: node_js.