ruby_koans_proxy_object.rb

    class Proxy
      attr_accessor :messages
      def initialize(target_object)
        @object = target_object
        @messages = []
      end
      def method_missing(method_name, *args, &block)
        @messages.push method_name
        @object.send(method_name, *args, &block)
      end
      def called?(method)
        @messages.include? method
      end
      def number_of_times_called(method)
        @messages.count{|obj| obj == method}
      end
    end