bag_of_matcher.rb

require 'set'

module BagOfMatchers

  class Bag
    def initialize(list)
      @list = Set.new(list)
    end
    
    def matches?(list)
      @compare_list = Set.new(list)
      @list == @compare_list
    end
    
    def failure_message
      "expected #{@list.inspect} to be a bag of #{@compare_list.inspect}, but it is not"
    end
    
    def negative_failure_message
      "expected #{@list.inspect} not to be a bag of #{@compare_list.inspect}, but it is"
    end
  end
    
  def be_bag_of(list)
    Bag.new(list)
  end
  
end