diff -r 000000000000 -r 6474c204b198 addon-sdk/source/test/private-browsing/tabs.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/test/private-browsing/tabs.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,27 @@
+'use strict';
+
+const { Ci } = require('chrome');
+const { openTab, closeTab } = require('sdk/tabs/utils');
+const { browserWindows } = require('sdk/windows');
+const { getOwnerWindow } = require('sdk/private-browsing/window/utils');
+const { isPrivate } = require('sdk/private-browsing');
+
+exports.testIsPrivateOnTab = function(assert) {
+  let window = browserWindows.activeWindow;
+
+  let chromeWindow = getOwnerWindow(window);
+
+  assert.ok(chromeWindow instanceof Ci.nsIDOMWindow, 'associated window is found');
+  assert.ok(!isPrivate(chromeWindow), 'the top level window is not private');
+
+  let rawTab = openTab(chromeWindow, 'data:text/html,<h1>Hi!</h1>', {
+    isPrivate: true
+  });
+
+  // test that the tab is private
+  assert.ok(rawTab.browser.docShell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing);
+  assert.ok(isPrivate(rawTab.browser.contentWindow));
+  assert.ok(isPrivate(rawTab.browser));
+
+  closeTab(rawTab);
+};