diff -r 000000000000 -r 6474c204b198 browser/base/content/test/general/browser_bug455852.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/base/content/test/general/browser_bug455852.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,16 @@
+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");
+}