The Tor Browser / file revision

 function test() {

   is(gBrowser.tabs.length, 1, "one tab is open");

   gBrowser.selectedBrowser.focus();

   isnot(document.activeElement, gURLBar.inputField, "location bar is not focused");

   var tab = gBrowser.selectedTab;

   gPrefService.setBoolPref("browser.tabs.closeWindowWithLastTab", false);

   EventUtils.synthesizeKey("w", { accelKey: true });

   is(tab.parentNode, null, "ctrl+w removes the tab");

   is(gBrowser.tabs.length, 1, "a new tab has been opened");

   is(document.activeElement, gURLBar.inputField, "location bar is focused for the new tab");

   if (gPrefService.prefHasUserValue("browser.tabs.closeWindowWithLastTab"))

     gPrefService.clearUserPref("browser.tabs.closeWindowWithLastTab");

 }