have_xml matcher Rspec 3 compatible

have_xml.rb

module XMLMatchers
  require 'libxml'
  require 'rspec/expectations'

  RSpec::Matchers.define :have_xml do |xpath, text|
    match do |body|
      parser = LibXML::XML::Parser.string body
      doc = parser.parse
      nodes = doc.find(xpath)

      return false if nodes.empty?
      if text
        return false unless nodes.any? {|node| node.content == text}
      end
      return true
    end

    failure_message_for_should do |body|
      "expected to find text '#{text}' in xml tag #{xpath} in:\n#{body}"
    end

    failure_message_for_should_not do |response|
      "expected not to find text #{text} xml tag #{xpath} in:\n#{body}"
    end

    description do
      "have xml tag #{xpath}"
    end
  end
end