module.exports = {

name: 'Exactly one main landmark',

validate: function($, fail) {
  var mainLandmarks = $("[role='main']");
  var count = mainLandmarks.length;
  if (count == 0) {
    fail('Found 0 elements with role="main".');
  } else if (count > 1) {
    fail('Found ' + count + ' elements with role="main":', mainLandmarks);
  }
}

}