class RSpec::Matchers::BuiltIn::MatchArray

def failure_message_for_should
  if actual.respond_to? :to_ary
    message =  "expected collection contained:  #{safe_sort(expected).inspect}\n"
    message += "actual collection contained:    #{safe_sort(actual).inspect}\n"
    message += "the missing elements were:      #{safe_sort(@missing_items).inspect}\n" unless @missing_items.empty?
    message += "the extra elements were:        #{safe_sort(@extra_items).inspect}\n"   unless @extra_items.empty?
  else
    message = "expected an array, actual collection was #{actual.inspect}"
  end
  message
end