gistfile1.rb

module Matchers
  class HaveNotice
    def initialize(contents)
      @contents = contents
    end

    def matches?(response_or_text)
      @actual = response_or_text.respond_to?(:body) ? response_or_text.body : response_or_text
      @actual.have_tag('div.notice', @contents)
    end

    def failure_message
      "expected response to contain #{@contents} but it didn't"
    end

    def negative_failure_message
      "expected response to not contain #{@contents} but it did"
    end
  end

  def have_notice(contents)
    HaveNotice.new(contents)
  end
end