version: 2
jobs:
  build:
    working_directory: ~/busy
    docker:
      - image: circleci/node:6
    steps:
      - checkout
      - run:
          name: install yarn
          command: 'sudo npm install -g yarn'
      - restore_cache:
          key: dependency-cache-{{ checksum "yarn.lock" }}
      - run:
          name: yarn install
          command: yarn install
      - save_cache:
          key: dependency-cache-{{ checksum "yarn.lock" }}
          paths:
            - ./node_modules
      - run:
          name: test
          command: yarn test
      # - run:
      #     name: lint
      #     command: yarn lint
      - run:
          name: code-coverage
          command: yarn test:coverage
      - store_artifacts:
          path: coverage
          prefix: coverage

version: 2
jobs:
  build:
    working_directory: ~/busy
    docker:
      - image: circleci/node:6
    steps:
      - checkout
      - run:
          name: install yarn
          command: 'sudo npm install -g yarn@0.27.4'
      - restore_cache:
          key: dependency-cache-{{ checksum "yarn.lock" }}
      - run:
          name: yarn install
          command: yarn install
      - save_cache:
          key: dependency-cache-{{ checksum "yarn.lock" }}
          paths:
            - ./node_modules
      - run:
          name: test
          command: yarn test
      # - run:
      #     name: lint
      #     command: yarn lint
      - run:
          name: code-coverage
          command: yarn test:coverage
      - store_artifacts:
          path: coverage
          prefix: coverage

Use yarn 0.27.4 on circleci
Use yarn 0.27.4 on circleci
