gistfile1.rb

Rspec::Matchers.define :match_nokogiri_selector do |selector|
  match do |doc|
    doc.at(selector) != nil
  end

  failure_message_for_should do |doc|
    "expected #{selector} to be found in \n#{doc.to_xml}"
  end

  failure_message_for_should_not do |doc|
    "expected that #{selector} would not be found in #{doc.to_xml}"
  end

  description do
    "match a selector of a nokogiri document"
  end
end

## Example
  xml = Nokogiri.XML(File.read(xml_path))
  xml.should match_nokogiri_selector "section article[class='stuff'] h1"