DC-Selenium

1-Dockerfile

# ./Dockerfile

FROM ruby:2.3-slim

RUN apt-get update && apt-get install -qq -y --no-install-recommends \
      build-essential nodejs
# Ensure that our apt package list is updated and install a few
# packages to ensure that we can compile assets (nodejs).

RUN mkdir -p /app
WORKDIR /app
COPY . .
# Add app files into docker image

COPY ./docker-entrypoint.sh /
RUN chmod +x /docker-entrypoint.sh
ENTRYPOINT ["/docker-entrypoint.sh"]
# Add bundle entry point to handle bundle cache

ENV BUNDLE_PATH=/bundle \
    BUNDLE_BIN=/bundle/bin \
    GEM_HOME=/bundle
ENV PATH="${BUNDLE_BIN}:${PATH}"
# Bundle installs with binstubs to our custom /bundle/bin volume path. Let system use those stubs.

2-docker-compose.yml

# ./docker-compose.yml

version: '3.1'
services:
  web:
    build: .
    command: >
      bash -c "
        RAILS_ENV=test puma -b tcp://0.0.0.0:3001 -d &&
        # Run test server detached
        
        puma -C config/puma.rb
        # Run web server
        "
    ports: ['3000:3000', '3001:3001']
      # Bind service ports to host machine.
    environment: 
      - SELENIUM_HOST=selenium
      - SELENIUM_PORT=4444
      - TEST_APP_HOST=web
      - TEST_PORT=3001
       # See ./test/test_helper.rb for Capybara & Selenium webdriver config
    volumes:
      - bundle_cache:/bundle
       # Map bundle cache to named volume
      - .:/app
       # Map /app files back to host drive, and visa versa
    stdin_open: true
    tty: true
      # Allow interactive byebug sessions.
    
  selenium:
    image: selenium/standalone-chrome-debug:3.0.1-germanium
      # Debug version enables VNC ability
    ports: ['4444:4444', '5900:5900']
      # Bind selenium port & VNC port
    logging:
      driver: none
      # Disable noisy logs.
      
volumes:
  bundle_cache:
  # Mount volume with default driver

3-docker-entrypoint.sh

# ./docker-entrypoint.sh

#!/bin/bash
# Bash script identifier

set -e
# Exit on fail

bundle check || bundle install --binstubs="$BUNDLE_BIN"
# Ensure all gems installed. Add binstubs to bin which has been added to PATH in Dockerfile.

exec "$@"
# Finally call command issued to the docker service

4-Gemfile

# ./Gemfile

source 'https://rubygems.org'
ruby '2.3.3'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.0.2'
# Use Puma as the app server
gem 'puma', '~> 3.0'

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platform: :mri
end

group :test do
  gem 'selenium-webdriver', '~> 3.0'
  gem 'minitest-rails-capybara', '~> 3.0'
end

4-test_helper.rb

# ./test/test_helper.rb

# Boilerplate Rails test code
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rails/test_help'

# Capybara config with docker-compose environment vars
require 'minitest/rails/capybara'
Capybara.app_host = "http://#{ENV['TEST_APP_HOST']}:#{ENV['TEST_PORT']}"
Capybara.javascript_driver = :selenium
Capybara.run_server = false

# Configure the Chrome driver capabilities & register
args = ['--no-default-browser-check', '--start-maximized']
caps = Selenium::WebDriver::Remote::Capabilities.chrome("chromeOptions" => {"args" => args})
Capybara.register_driver :selenium do |app|
  Capybara::Selenium::Driver.new(
      app,
      browser: :remote,
      url: "http://#{ENV['SELENIUM_HOST']}:#{ENV['SELENIUM_PORT']}/wd/hub",
      desired_capabilities: caps
  )
end

5-rails_files.rb

# ./config/routes.rb
Rails.application.routes.draw do
  root "welcome#index"
end

# ./app/controllers/welcome_cotnroller.rb
class WelcomeController < ApplicationController
  # Empty controller will automatically load 'index' view.
end

# ./app/views/welcome/index.html.erb
<h1>Hello World!</h1>

# ./test/acceptance/welcome_page.rb
require 'test_helper'
describe "Can Access Home", :capybara do
  it "has content", js: true do
    visit root_path
    page.must_have_content "Hello World!"
  end
end