Circle CI 2.1 configuration step for Ruby / Rails / Redis / Postgres workflow with tests + system tests running in parallel

config.yml

# Ruby CircleCI 2.0 configuration file
#
# Check https://circleci.com/docs/2.0/language-ruby/ for more details
#
version: 2.1

executors:
  my-executor:
    docker:
      # Main image to be used within this configuration
      - image: circleci/ruby:2.6.3-node-browsers
        environment: # environment variables for database
          BUNDLER_VERSION: 2.0.1
          DATABASE_URL: "postgres://postgres@localhost:5432/test"
          MINITEST_CI: 1
          NODE_ENV: test
          RACK_ENV: test
          RAILS_ENV: test

      - image: circleci/redis:3.2-alpine

      # Environment variables for database need to match DATABASE_URL
      - image: circleci/postgres:10-alpine-ram
        environment:
          POSTGRES_DB: test
          POSTGRES_USER: postgres

references:
  prepare_directories: &prepare_directories
    run:
      name: Restore Rails work directories missing from repository
      command: mkdir -p log tmp

  upgrade_gem_bundler: &upgrade_gem_bundler
    run:
      name: Upgrade rubygems and Bundler to latest versions
      command: |
        gem update --system
        gem update bundler

  install_dependencies: &install_dependencies
    run:
      name: Install Linux dependencies
      command: sudo apt-get install graphicsmagick

  # Install and cache all gems
  restore_bundler_cache: &restore_bundler_cache
    restore_cache:
      keys:
        - bundler-2019-05-06-{{ checksum "Gemfile.lock" }}
        - bundler-2019-05-06

  bundle_install: &bundle_install
    run:
      name: Install gems
      command: bundle install --deployment --jobs=4 --retry=3

  save_bundler_cache: &save_bundler_cache
    save_cache:
      key: bundler-2019-05-06-{{ checksum "Gemfile.lock" }}
      paths:
        - vendor/bundle

  restore_yarn_cache: &restore_yarn_cache
    restore_cache:
      keys:
        - yarn-2019-05-06-{{ checksum "package.json" }}
        - yarn-2019-05-06

  yarn_install: &yarn_install
    run:
      name: Install NPM packages
      command: yarn install

  save_yarn_cache: &save_yarn_cache
    save_cache:
      key: yarn-2019-05-06-{{ checksum "package.json" }}
      paths:
        - node_modules

  restore_assets_cache: &restore_assets_cache
    restore_cache:
      keys:
        - sprockets-webpacker-2019-05-06-{{ .Branch }}
        - sprockets-webpacker-2019-05-06

  precompile_assets: &precompile_assets
    run: bundle exec rake assets:precompile

  save_assets_cache: &save_assets_cache
    save_cache:
      key: sprockets-webpacker-2019-05-06-{{ .Branch }}
      paths:
        - public/assets
        - public/packs
        - public/packs-test
        - tmp/cache/assets
        - tmp/cache/webpacker

  init_db: &init_db
    run:
      name: Initialize test database
      command: bundle exec rake db:test:prepare

  test: &test
    run:
      name: Run non-system tests
      command: bundle exec rake test

  test_system: &test_system
    run:
      name: Run system tests on Chrome
      command: CAPYBARA_DRIVER=chrome bundle exec rake test:system

    # Firefox is not reliable enough, we have way too much false positives
    # We need to run its tests in a separate process, for speed and clarity
    # - run:
    #     name: Run system tests on Firefox
    #     command: CAPYBARA_DRIVER=firefox bundle exec rake test:system

jobs:
  prepare:
    executor: my-executor
    steps:
      - checkout
      - <<: *prepare_directories
      - <<: *upgrade_gem_bundler
      - <<: *restore_bundler_cache
      - <<: *bundle_install
      - <<: *save_bundler_cache
      - <<: *restore_yarn_cache
      - <<: *yarn_install
      - <<: *save_yarn_cache
      - <<: *restore_assets_cache
      - <<: *precompile_assets
      - <<: *save_assets_cache

  tests:
    executor: my-executor
    steps:
      - checkout
      - <<: *prepare_directories
      - <<: *upgrade_gem_bundler
      - <<: *restore_bundler_cache
      - <<: *bundle_install
      - <<: *save_bundler_cache
      - <<: *restore_yarn_cache
      - <<: *yarn_install
      - <<: *save_yarn_cache
      - <<: *restore_assets_cache
      - <<: *precompile_assets
      - <<: *save_assets_cache
      - <<: *install_dependencies
      - <<: *init_db
      - <<: *test

  system-tests:
    executor: my-executor
    steps:
      - checkout
      - <<: *prepare_directories
      - <<: *upgrade_gem_bundler
      - <<: *restore_bundler_cache
      - <<: *bundle_install
      - <<: *save_bundler_cache
      - <<: *restore_yarn_cache
      - <<: *yarn_install
      - <<: *save_yarn_cache
      - <<: *restore_assets_cache
      - <<: *precompile_assets
      - <<: *save_assets_cache
      - <<: *install_dependencies
      - <<: *init_db
      - <<: *test_system

workflows:
  "Run tests":
    jobs:
      - prepare
      - tests:
          requires:
            - prepare
      - system-tests:
          requires:
            - prepare