[RAILS] Build a browser test environment using Capybara in the Docker development environment

Overview

I summarized how to build an RSpec test environment in the docker development environment. Since I am a beginner and self-taught, I think there are some mistakes and better ways to do it, but I would be grateful if you could point out at that time.

I referred to the following article. I tried RSpec System test with Selenium Docker on Rails on Docker.

Introduction

Previously, I posted an article about browser test error resolution in Cannot run browser test in Rails development using Docker. If you comment and use docker-compose to run chrome itself as one of the services, I was advised that it would be easy to test without polluting the Rails environment, so I tried it. Thank you for pointing out!

1. Add chrome service to docker-compose.yml

The image used is standalone-chrome, which is the one with Chrome installed from the beginning.

docker-compose.yml

version: '3'
services:
  web:
    build: .
    command: bundle exec rails s -p 3000 -b '0.0.0.0'
    volumes:
      - .:/[app name]
    ports:
      - 3000:3000
    depends_on:
      - db
      - chrome　#← Add
    tty: true
    stdin_open: true
  db:
    image: mysql:5.7
    volumes:
      - db-volume:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: password
　#↓ Add
  chrome:
    image: selenium/standalone-chrome:latest
    ports:
      - 4444:4444
　#↑ Add
volumes:
  db-volume:

2. Introduction of RSpec

Add gem of rspec-rails

Gemfile

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  gem 'rspec-rails', '~> 4.0.1'  #add to
  gem 'factory_bot_rails', '~>4.11'
end

Install gem.

$ docker-compose build

• Don't forget to restart the container after building

Install RSpec

$ docker-compose run web rails g rspec:install

Next, in the file created by installation, describe the settings in "rails_helper.rb". Set to use docker-selenium container browser when running RSpec.

/spec/rails_helper.rb

#~
Capybara.register_driver :remote_chrome do |app|
  url = "http://chrome:4444/wd/hub"
  caps = ::Selenium::WebDriver::Remote::Capabilities.chrome(
    "goog:chromeOptions" => {
      "args" => [
        "no-sandbox",
        "headless",
        "disable-gpu",
        "window-size=1680,1050"
      ]
    }
  )
  Capybara::Selenium::Driver.new(app, browser: :remote, url: url, desired_capabilities: caps)
end

#~

RSpec.configure do |config|
  
  config.before(:each, type: :system) do
    driven_by :rack_test
  end

  config.before(:each, type: :system, js: true) do
    driven_by :remote_chrome
    Capybara.server_host = IPSocket.getaddress(Socket.gethostname)
    Capybara.server_port = 4444
    Capybara.app_host = "http://#{Capybara.server_host}:#{Capybara.server_port}"
  end
#~
end

Finally, edit .rspec to read the settings in rails_helper.rb.

.rspec

- --require spec_helper
+ --require rails_helper

that's all.

Now let's write a test and see if we can run it.

#When the container starts
$ docker-compose exec web rspec [rspec test file path]

I was able to see a hard copy of my browser when the test failed.