diff -r 000000000000 -r 6474c204b198 browser/metro/base/tests/mochitest/browser_private_browsing.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/metro/base/tests/mochitest/browser_private_browsing.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,37 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* 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/. */
+
+"use strict";
+
+function test() {
+  runTests();
+}
+
+gTests.push({
+  desc: "Private tab sanity check",
+  run: function() {
+    let tab = Browser.addTab("about:mozilla");
+    is(tab.isPrivate, false, "Tabs are not private by default");
+    is(tab.chromeTab.hasAttribute("private"), false,
+      "non-private tab has no private attribute");
+
+    let child = Browser.addTab("about:mozilla", false, tab);
+    is(child.isPrivate, false, "Child of a non-private tab is not private");
+
+    Browser.closeTab(child, { forceClose: true });
+    Browser.closeTab(tab, { forceClose: true });
+
+    tab = Browser.addTab("about:mozilla", false, null, { private: true });
+    is(tab.isPrivate, true, "Create a private tab");
+    is(tab.chromeTab.getAttribute("private"), "true",
+      "private tab has private attribute");
+
+    child = Browser.addTab("about:mozilla", false, tab);
+    is(child.isPrivate, true, "Child of a private tab is private");
+
+    Browser.closeTab(child, { forceClose: true });
+    Browser.closeTab(tab, { forceClose: true });
+  }
+});