markup_snapshot.rb

#!/usr/bin/env ruby-1.9.3-p392@markup_snapshot

# Our pixel hero wants to know when we change the HTML layout. This script runs
# selected cucumber features in given branch/sha1 and makes snapshots in HTML
# and HAML, original and stripped.
#
# Prerequisites:
# you
#  * have rails project
#  * use cucumber with capybara
#  * use git
#  * use rvm & bundler
#  * have bash in your path

# Setup:
#   rvm use ruby-1.9.3-p392@markup_snapshot --create

require 'pathname'
require 'fileutils'

class MarkupSnapshot
  Root  = Pathname.pwd.join('tmp/markup_snapshots').expand_path
  Cukes = []
  StepsPath = Root.join('snapshot_steps.rb')

  class Cuke < Struct.new(:name, :content)
    def initialize(*a)
      super
      name.gsub!(/\W/i,'_')
      unless name =~ /\.feature$/
        self.name += '.feature'
      end
    end
  end

  def self.cuke(name, content)
    Cukes << Cuke.new(name,content)
  end

  def self.run(*a)
    new(*a).run
  end

  attr_reader :commit
  def initialize(commit=nil)
    @commit = commit
  end

  def run
    #checkout
    #bundle
    #migrate
    #run_cukes
    #install_gems
    dump_hamls
  end

  private

  def install_gems
    html2haml_version = '1.0.1'
    sys %Q~gem list | grep html2haml | grep #{html2haml_version} || gem install html2haml --no-ri --no-rdoc -v #{html2haml_version}~
    nokogiri_version = '1.5.9'
    sys %Q~gem list | grep nokogiri | grep #{nokogiri_version} || gem install nokogiri --no-ri --no-rdoc -v #{nokogiri_version}~
  end

  def checkout
    if commit
      sys %Q~git checkout #{commit}~
    end
  end

  def bundle
    sys_project %Q~bundle check || bundle install~
  end

  def migrate
    sys_project %Q~bundle exec rake db:drop db:create db:migrate RAILS_ENV=test~
  end

  def root
    Root.join commit ? commit : 'current'
  end

  def run_cukes
    FileUtils.mkdir_p root
    write_steps
    write_cukes
    cukes = Cukes.map { |cuke| Root.join(cuke.name) }
    sys_project %Q~bundle exec cucumber -r features/ -r #{StepsPath} #{cukes.join(' ')}~
  end

  # TODO run wget mirror to save all assets
  def write_steps
    File.open StepsPath, 'w' do |f|
      f.puts <<-EOSTEPS
        When /^I take a snapshot$/ do
          require 'capybara/util/save_and_open_page'
          @snapshot_index ||= 0
          @snapshot_index += 1
          Capybara.save_and_open_page_path = #{root.to_s.inspect}
          Capybara.save_page(body, @snapshot_index.to_s + '.html')
        end
      EOSTEPS
    end
  end

  def write_cukes
    Cukes.each do |cuke|
      File.open Root.join(cuke.name), 'w' do |f|
        f.write cuke.content
      end
    end
  end

  def htmls
    @htmls ||= [].tap do |files|
      root.find do |html|
        if html.fnmatch('*.html')
          files << html
        end
      end
    end
  end

  def dump_hamls
    require 'nokogiri'
    htmls.each do |html|
      dump_haml(html)

      stripped = html.sub(/.html$/, '.stripped.html')
      File.open(stripped, 'w') { |f| f.print strip_text_from_html(File.read(html)) }

      dump_haml(stripped)
    end
  end

  def dump_haml(html)
    haml = html.sub(/.html$/, '.haml')
    sys 'html2haml', '--trace', html.to_s, haml.to_s
  end

  def strip_text_from_html(html)
    Nokogiri::HTML.parse(html).tap do |doc|
      doc.css('*').each do |node|
        node[:alt] = nil if node[:alt]
        if node.text?
          node.remove
        else
          node.children.each do |child|
            child.remove if child.text?
          end
        end
      end
    end.to_s
  end

  # runs the given command and tells the user about it
  def sys(*a)
    line = a.join(' ')
    STDERR.puts " >>> #{line}"
    system line
  end

  # runs the given command in the original rvm environment
  def sys_project(*a)
    line = a.join(' ')
    STDERR.puts " >>> #{line}"
    line = 'source .rvmrc && ' + line
    system 'bash', '-l', '-c', line
  end
end

MarkupSnapshot.cuke 'homepage', <<EOCUKE
Feature: Homepage
  Scenario: empty
    Given I am on the home page
     Then I take a snapshot
EOCUKE

# Add more cukes here

MarkupSnapshot.run(ARGV.first)
# vim:filetype=ruby