machine:
  pre:
    - mkdir ~/.yarn-cache
  node:
    version: stable
dependencies:
  pre:
    - curl -o- -L https://yarnpkg.com/install.sh | bash
  cache_directories:
    - ~/.yarn-cache
  override:
    - yarn install
test:
  override:
    - yarn test

machine:
  pre:
    - mkdir ~/.yarn-cache
  node:
    version: stable
dependencies:
  pre:
    # Install Yarn
    - sudo apt-key adv --fetch-keys http://dl.yarnpkg.com/debian/pubkey.gpg
    - echo "deb http://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
    - sudo apt-get update -qq
    - sudo apt-get install -y -qq yarn
  cache_directories:
    - "~/.yarn-cache"
  override:
    - yarn install
test:
  override:
    - yarn test

Use official Yarn Circle config
Use official Yarn Circle config
