diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_967000_button_feeds.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_967000_button_feeds.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,60 @@
+/* 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";
+
+const TEST_PAGE = "http://mochi.test:8888/browser/browser/components/customizableui/test/support/feeds_test_page.html";
+const TEST_FEED = "http://mochi.test:8888/browser/browser/components/customizableui/test/support/test-feed.xml"
+
+let newTab = null;
+let initialLocation = gBrowser.currentURI.spec;
+
+add_task(function() {
+  info("Check Subscribe button functionality");
+
+  // add the Subscribe button to the panel
+  CustomizableUI.addWidgetToArea("feed-button",
+                                  CustomizableUI.AREA_PANEL);
+
+  // check the button's functionality
+  yield PanelUI.show();
+
+  let feedButton = document.getElementById("feed-button");
+  ok(feedButton, "The Subscribe button was added to the Panel Menu");
+  is(feedButton.getAttribute("disabled"), "true", "The Subscribe button is initially disabled");
+
+  let panelHidePromise = promisePanelHidden(window);
+  PanelUI.hide();
+  yield panelHidePromise;
+
+  newTab = gBrowser.selectedTab;
+  yield promiseTabLoadEvent(newTab, TEST_PAGE);
+
+  yield PanelUI.show();
+
+  yield waitForCondition(function() !feedButton.hasAttribute("disabled"));
+  ok(!feedButton.hasAttribute("disabled"), "The Subscribe button gets enabled");
+
+  feedButton.click();
+  yield promiseTabLoadEvent(newTab, TEST_FEED);
+
+  is(gBrowser.currentURI.spec, TEST_FEED, "Subscribe page opened");
+  ok(!isPanelUIOpen(), "Panel is closed");
+
+  if(isPanelUIOpen()) {
+    panelHidePromise = promisePanelHidden(window);
+    PanelUI.hide();
+    yield panelHidePromise;
+  }
+});
+
+add_task(function asyncCleanup() {
+  // reset the panel UI to the default state
+  yield resetCustomization();
+  ok(CustomizableUI.inDefaultState, "The UI is in default state again.");
+
+  // restore the initial location
+  gBrowser.addTab(initialLocation);
+  gBrowser.removeTab(newTab);
+});