RSpec, Capybara, CircleCI And Chrome Headless Webdriver Configuration

# Gemfile
group :development, :test do
  gem 'capybara'
  gem 'selenium-webdriver'
end

$ brew install chromedriver

$ brew upgrade chromedriver

# spec/support/config/capybara.rb
JS_DRIVER = :selenium_chrome_headless

Capybara.default_driver = :rack_test
Capybara.javascript_driver = JS_DRIVER
Capybara.default_max_wait_time = 2

RSpec.configure do |config|
  config.before(:each) do |example|
    Capybara.current_driver = JS_DRIVER if example.metadata[:js]
    Capybara.current_driver = :selenium if example.metadata[:selenium]
    Capybara.current_driver = :selenium_chrome if example.metadata[:selenium_chrome]
  end

  config.after(:each) do
    Capybara.use_default_driver
  end
end

# spec/rails_helper.rb

# The following line is provided for convenience purposes. It has the downside
# of increasing the boot-up time by auto-requiring all files in the support
# directory. Alternatively, in the individual `*_spec.rb` files, manually
# require only the support files necessary.
Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }

# spec/features/home_spec.rb
feature 'Homepage Features' do
  before { visit root_path }

  # it won't run js code but it is fast
  it do
    expect(page).to have_content 'Hello World'
  end

  # it will run js code
  it '', :js do
    expect(page).to have_content 'Hello World'
  end

  # it will open Firefox
  # remove x from xit to run the test in Firefox on your machine to preview
  xit '', :selenium do
    expect(page).to have_content 'Hello World'
  end

  # it will open Chrome
  # remove x from xit to run the test in Chrome on your machine to preview
  xit '', :selenium_chrome do
    expect(page).to have_content 'Hello World'
  end
end

# .circleci/config.yml
version: 2
jobs:
  build:
    parallelism: 1
    working_directory: ~/project-name
    docker:
      # this is important to use proper image with browsers support
      - image: circleci/ruby:2.4.2-node-browsers
        environment:
          PGHOST: 127.0.0.1
          PGUSER: project-name
          RAILS_ENV: test
      - image: circleci/postgres:9.4.12-alpine
        environment:
          POSTGRES_DB: project-name_test
          POSTGRES_PASSWORD: ""
          POSTGRES_USER: project-name
      - image: redis:3.2.7
    steps:
      - checkout

      # Restore bundle cache
      - type: cache-restore
        # remove space between { {
        key: project-name-{ { checksum "Gemfile.lock" }}

      # Bundle install dependencies
      - run: bundle install --path vendor/bundle

      # Store bundle cache
      - type: cache-save
        # remove space between { {
        key: project-name-{ { checksum "Gemfile.lock" }}
        paths:
          - vendor/bundle

      # Prepare .env, useful if you use dotenv gem
      - run: cp .env.example .env

      # Database setup
      - run: bundle exec rake db:create
      - run: bundle exec rake db:schema:load

      # Run rspec in parallel
      - type: shell
        command: |
          bundle exec rspec --profile 10 \
                            --format RspecJunitFormatter \
                            --out /tmp/test-results/rspec.xml \
                            --format progress

      # Save artifacts
      - type: store_test_results
        path: /tmp/test-results

# .circleci/config.yml
jobs:
  build:
    parallelism: 6

  steps:
    # some tests that are not balanced and executed only on first CI node
    - run: case $CIRCLE_NODE_INDEX in 0) npm test ;; esac

    # auto-balancing CI build time execution to be flat and optimal (as fast as possible).
    # Queue Mode does dynamic tests allocation so the previous not balanced run command won't
    # create a bottleneck on the CI node
    - run:
      name: RSpec via knapsack_pro Queue Mode
      command: |
        # export word is important here!
        export RAILS_ENV=test
        bundle exec rake "knapsack_pro:queue:rspec[--format documentation]"