gistfile1.rb

class HeroPage < AR::Base
  def online_total!
    save!
  end
end

class HeroPageTest < ActiveSupport::TestCase
  test "#total_in_aud includes the registration total" do
    mock_hero_page = Class.new SimpleDelegator do
      def save!
        raise 'I HATE YOU'
      end
    end
    hero_page = mock_hero_page.new(HeroPage.new)
    assert hero_page.online_total! # => Raises with validation errors
  end
end