docs: function assertLoadedUrlEqual(controller, targetUrl) {
    var locationBar = new elementslib.ID(controller.window.document, "urlbar");
    var currentURL = locationBar.getNode().value;
  
    // Load the target URL
    controller.open(targetUrl);
    controller.waitForPageLoad();
  
    // Check the same web page has been opened
    controller.waitForEval("subject.targetURL.value == subject.currentURL", gTimeout, 100,
                           {targetURL: locationBar.getNode(),  currentURL: currentURL});
  }