Extend rspec with a method similar to should_receive but that invokes the original method

gistfile1.rb

module RSpec
  module Mocks
    module Methods
      def should_receive_invoke(message, opts={})
        original_method = self.method(message.to_sym)
        should_receive(message, opts) do |*args|
          original_method.call(*args)
        end
      end
    end
  end
end