diff -r 000000000000 -r 6474c204b198 browser/base/content/test/general/browser_bug767836_perwindowpb.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/base/content/test/general/browser_bug767836_perwindowpb.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,83 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function test() {
+  //initialization
+  waitForExplicitFinish();
+  let newTabPrefName = "browser.newtab.url";
+  let newTabURL;
+  let testURL = "http://example.com/";
+  let mode;
+
+  function doTest(aIsPrivateMode, aWindow, aCallback) {
+    openNewTab(aWindow, function () {
+      if (aIsPrivateMode) {
+        mode = "per window private browsing";
+        newTabURL = "about:privatebrowsing";
+      } else {
+        mode = "normal";
+        newTabURL = Services.prefs.getCharPref(newTabPrefName) || "about:blank";
+      }
+
+      // Check the new tab opened while in normal/private mode
+      is(aWindow.gBrowser.selectedBrowser.currentURI.spec, newTabURL,
+        "URL of NewTab should be " + newTabURL + " in " + mode +  " mode");
+      // Set the custom newtab url
+      Services.prefs.setCharPref(newTabPrefName, testURL);
+      ok(Services.prefs.prefHasUserValue(newTabPrefName), "Custom newtab url is set");
+
+      // Open a newtab after setting the custom newtab url
+      openNewTab(aWindow, function () {
+        is(aWindow.gBrowser.selectedBrowser.currentURI.spec, testURL,
+           "URL of NewTab should be the custom url");
+
+        // clear the custom url preference
+        Services.prefs.clearUserPref(newTabPrefName);
+        ok(!Services.prefs.prefHasUserValue(newTabPrefName), "No custom newtab url is set");
+
+        aWindow.gBrowser.removeTab(aWindow.gBrowser.selectedTab);
+        aWindow.gBrowser.removeTab(aWindow.gBrowser.selectedTab);
+        aWindow.close();
+        aCallback()
+      });
+    });
+  }
+
+  function testOnWindow(aIsPrivate, aCallback) {
+    whenNewWindowLoaded({private: aIsPrivate}, function(win) {
+      executeSoon(function() aCallback(win));
+    });
+  }
+
+  // check whether any custom new tab url has been configured
+  ok(!Services.prefs.prefHasUserValue(newTabPrefName), "No custom newtab url is set");
+
+  // test normal mode
+  testOnWindow(false, function(aWindow) {
+    doTest(false, aWindow, function() {
+      // test private mode
+      testOnWindow(true, function(aWindow) {
+        doTest(true, aWindow, function() {
+          finish();
+        });
+      });
+    });
+  });
+}
+
+function openNewTab(aWindow, aCallback) {
+  // Open a new tab
+  aWindow.BrowserOpenTab();
+
+  let browser = aWindow.gBrowser.selectedBrowser;
+  if (browser.contentDocument.readyState == "complete") {
+    executeSoon(aCallback);
+    return;
+  }
+
+  browser.addEventListener("load", function onLoad() {
+    browser.removeEventListener("load", onLoad, true);
+    executeSoon(aCallback);
+  }, true);
+}
\ No newline at end of file