gistfile1.rb

class Item
  def does_something(publishing_house = PublishingHouse.new)
    publishing_house.publish(@document)
  end
end

it 'publishes the document' do
  publishing_house = stub('PublishingHouse')
  publishing_house.should_receive(:publish).with(document)

  Item.new(document).does_something(publishing_house)
end