diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_967000_button_charEncoding.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_967000_button_charEncoding.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,66 @@
+/* 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/test_967000_charEncoding_page.html";
+
+let newTab;
+let initialLocation = gBrowser.currentURI.spec;
+
+add_task(function() {
+  info("Check Character Encoding button functionality");
+
+  // add the Character Encoding button to the panel
+  CustomizableUI.addWidgetToArea("characterencoding-button",
+                                  CustomizableUI.AREA_PANEL);
+
+  // check the button's functionality
+  yield PanelUI.show();
+
+  let charEncodingButton = document.getElementById("characterencoding-button");
+  ok(charEncodingButton, "The Character Encoding button was added to the Panel Menu");
+  is(charEncodingButton.getAttribute("disabled"), "true",
+     "The Character encoding button is initially disabled");
+
+  let panelHidePromise = promisePanelHidden(window);
+  PanelUI.hide();
+  yield panelHidePromise;
+
+  newTab = gBrowser.selectedTab;
+  yield promiseTabLoadEvent(newTab, TEST_PAGE)
+
+  yield PanelUI.show();
+  ok(!charEncodingButton.hasAttribute("disabled"), "The Character encoding button gets enabled");
+  charEncodingButton.click();
+
+  let characterEncodingView = document.getElementById("PanelUI-characterEncodingView");
+  ok(characterEncodingView.hasAttribute("current"), "The Character encoding panel is displayed");
+
+  let pinnedEncodings = document.getElementById("PanelUI-characterEncodingView-pinned");
+  let charsetsList = document.getElementById("PanelUI-characterEncodingView-charsets");
+  ok(pinnedEncodings, "Pinned charsets are available");
+  ok(charsetsList, "Charsets list is available");
+
+  let checkedButtons = characterEncodingView.querySelectorAll("toolbarbutton[checked='true']");
+  is(checkedButtons.length, 2, "There should be 2 checked items (1 charset, 1 detector).");
+  is(checkedButtons[0].getAttribute("label"), "Unicode", "The unicode encoding is correctly selected");
+  is(characterEncodingView.querySelectorAll("#PanelUI-characterEncodingView-autodetect toolbarbutton[checked='true']").length,
+     1,
+     "There should be 1 checked detector.");
+
+  panelHidePromise = promisePanelHidden(window);
+  PanelUI.hide();
+  yield panelHidePromise;
+});
+
+add_task(function asyncCleanup() {
+  // reset the panel 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);
+});