JS confirm dialog testing with Cucumber, Capybara, Rails 2 and 3

rails2_feature.feature

Then I expect to click "OK" on a confirmation box saying "Are you sure?"
And I press "Delete"
And the confirmation box should have been displayed

rails2_steps.rb

When /^I expect to click "([^"]*)" on a confirmation box saying "([^"]*)"$/ do |option, message|
  retval = (option == 'OK') ? 'true' : 'false'
  page.evaluate_script("window.confirm = function (msg) {
    document.cookie = msg
    return #{retval}
  }")
  @expected_message = message.gsub("\\n", "\n")
end

When /^the confirmation box should have been displayed$/ do
  assert page.evaluate_script('document.cookie').include?(@expected_message),
         "Expected confirm box with message: '#{@expected_message}'" +
         "                              got: '#{page.evaluate_script('document.cookie')}'"
end

rails3_feature.feature

Then "Delete" should have a confirmation saying "Are you sure?"

rails3_steps.rb

When /^"([^\"]*)" should have a confirmation saying "([^\"]*)"$/ do |locator, message|
  el = find_button(locator) || find_link(locator)
  el['data-confirm'].should eql(message.gsub("\\n", "\n"))
end