Gitlab CI Config for Minitest/system tests

.gitlab-ci.yml

image: "ruby:2.7"
services:
  - postgres
  - redis:latest
  
variables:
  RAILS_ENV: test
  POSTGRES_DB: my_app_test
  POSTGRES_USER: postgres
  POSTGRES_PASSWORD: "password"
  DATABASE_URL: "postgresql://postgres:password@postgres:5432/my_app_test"
  SELENIUM_URL: http://selenium__standalone-chrome:4444/wd/hub
before_script:
  - apt-get update -qq && apt-get install -y -qq nodejs
  # Install yarn as outlined in (https://yarnpkg.com/lang/en/docs/install/#alternatives-stable)
  - curl -o- -L https://yarnpkg.com/install.sh | bash
  # Make available in the current terminal
  - export PATH="$HOME/.yarn/bin:$HOME/.config/yarn/global/node_modules/.bin:$PATH"
  - node -v
  - yarn -v
  - ruby -v
  - which ruby
  - gem install bundler --no-document
  - bundle install --jobs $(nproc)  "${FLAGS[@]}" --path vendor
  - yarn install
  # Database setup
  - bin/rails db:setup
test:
  stage: test
  cache:
    paths:
      - node_modules/
      - .yarn
      - vendor
  script:
  - bundle exec rails test
  only:
  - master
  - merge_requests
system_test:
  stage: test
  cache:
    paths:
      - node_modules/
      - .yarn
      - vendor
      - public/packs-test
  artifacts:
    when: on_failure
    paths:
      - tmp/screenshots
      - /tmp/chrome.log
      - log/test.log
    expire_in: 1 week
  script:
  - bundle exec rails test:system
  only:
  - master
  - merge_requests
  services:
    - postgres
    - redis:latest
    - selenium/standalone-chrome:latest

application_system_test_case.rb

require "test_helper"
Capybara.server = :puma, {Silent: true}
class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  if ENV['SELENIUM_URL']
    # Specify the driver (remote selenium, read: CI)
    driven_by :selenium, using: :chrome, screen_size: [1920, 1080],
                         options: {url: ENV["SELENIUM_URL"],
                                   args: %w[headless disable-popup-blocking disable-gpu no-sandbox
                                            disable-dev-shm-usage window-size=1920,1080
                                            enable-features=NetworkService],}
    # Make the test app listen to outside requests, for the remote Selenium instance.
    Capybara.server_host = "0.0.0.0"
  else
    driven_by :selenium, using: :headless_chrome, screen_size: [1400, 1400]
  end
  setup do
    if ENV['SELENIUM_URL']
      # Get the application container's IP
      ip = Socket.ip_address_list.detect(&:ipv4_private?).ip_address
      # Use the IP instead of localhost so Capybara knows where to direct Selenium
      host! "http://#{ip}:#{Capybara.server_port}"
    end
  end
end

Gemfile

# ...

group :test do
  gem 'webdrivers', require: !ENV['SELENIUM_URL']
end