diff -r 000000000000 -r 6474c204b198 browser/components/customizableui/test/browser_914138_widget_API_overflowable_toolbar.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/customizableui/test/browser_914138_widget_API_overflowable_toolbar.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,131 @@
+/* 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";
+
+let navbar = document.getElementById(CustomizableUI.AREA_NAVBAR);
+let overflowList = document.getElementById(navbar.getAttribute("overflowtarget"));
+
+const kTestBtn1 = "test-addWidgetToArea-overflow";
+const kTestBtn2 = "test-removeWidgetFromArea-overflow";
+const kTestBtn3 = "test-createWidget-overflow";
+const kHomeBtn = "home-button";
+const kDownloadsBtn = "downloads-button";
+const kSearchBox = "search-container";
+const kStarBtn = "bookmarks-menu-button";
+
+let originalWindowWidth;
+
+// Adding a widget should add it next to the widget it's being inserted next to.
+add_task(function() {
+  originalWindowWidth = window.outerWidth;
+  createDummyXULButton(kTestBtn1, "Test");
+  ok(!navbar.hasAttribute("overflowing"), "Should start with a non-overflowing toolbar.");
+  ok(CustomizableUI.inDefaultState, "Should start in default state.");
+
+  window.resizeTo(400, window.outerHeight);
+  yield waitForCondition(() => navbar.hasAttribute("overflowing"));
+  ok(navbar.hasAttribute("overflowing"), "Should have an overflowing toolbar.");
+  ok(!navbar.querySelector("#" + kHomeBtn), "Home button should no longer be in the navbar");
+  let homeBtnNode = overflowList.querySelector("#" + kHomeBtn);
+  ok(homeBtnNode, "Home button should be overflowing");
+  ok(homeBtnNode && homeBtnNode.getAttribute("overflowedItem") == "true", "Home button should have overflowedItem attribute");
+
+  let placementOfHomeButton = CustomizableUI.getWidgetIdsInArea(navbar.id).indexOf(kHomeBtn);
+  CustomizableUI.addWidgetToArea(kTestBtn1, navbar.id, placementOfHomeButton);
+  ok(!navbar.querySelector("#" + kTestBtn1), "New button should not be in the navbar");
+  let newButtonNode = overflowList.querySelector("#" + kTestBtn1);
+  ok(newButtonNode, "New button should be overflowing");
+  ok(newButtonNode && newButtonNode.getAttribute("overflowedItem") == "true", "New button should have overflowedItem attribute");
+  let nextEl = newButtonNode && newButtonNode.nextSibling;
+  is(nextEl && nextEl.id, kHomeBtn, "Test button should be next to home button.");
+
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+  yield waitForCondition(() => !navbar.hasAttribute("overflowing"));
+  ok(!navbar.hasAttribute("overflowing"), "Should not have an overflowing toolbar.");
+  ok(navbar.querySelector("#" + kHomeBtn), "Home button should be in the navbar");
+  ok(homeBtnNode && (homeBtnNode.getAttribute("overflowedItem") != "true"), "Home button should no longer have overflowedItem attribute");
+  ok(!overflowList.querySelector("#" + kHomeBtn), "Home button should no longer be overflowing");
+  ok(navbar.querySelector("#" + kTestBtn1), "Test button should be in the navbar");
+  ok(!overflowList.querySelector("#" + kTestBtn1), "Test button should no longer be overflowing");
+  ok(newButtonNode && (newButtonNode.getAttribute("overflowedItem") != "true"), "New button should no longer have overflowedItem attribute");
+  let el = document.getElementById(kTestBtn1);
+  if (el) {
+    CustomizableUI.removeWidgetFromArea(kTestBtn1);
+    el.remove();
+  }
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+});
+
+// Removing a widget should remove it from the overflow list if that is where it is, and update it accordingly.
+add_task(function() {
+  createDummyXULButton(kTestBtn2, "Test");
+  ok(!navbar.hasAttribute("overflowing"), "Should start with a non-overflowing toolbar.");
+  ok(CustomizableUI.inDefaultState, "Should start in default state.");
+  CustomizableUI.addWidgetToArea(kTestBtn2, navbar.id);
+  ok(!navbar.hasAttribute("overflowing"), "Should still have a non-overflowing toolbar.");
+
+  window.resizeTo(400, window.outerHeight);
+  yield waitForCondition(() => navbar.hasAttribute("overflowing"));
+  ok(navbar.hasAttribute("overflowing"), "Should have an overflowing toolbar.");
+  ok(!navbar.querySelector("#" + kTestBtn2), "Test button should not be in the navbar");
+  ok(overflowList.querySelector("#" + kTestBtn2), "Test button should be overflowing");
+
+  CustomizableUI.removeWidgetFromArea(kTestBtn2);
+
+  ok(!overflowList.querySelector("#" + kTestBtn2), "Test button should not be overflowing.");
+  ok(!navbar.querySelector("#" + kTestBtn2), "Test button should not be in the navbar");
+  ok(gNavToolbox.palette.querySelector("#" + kTestBtn2), "Test button should be in the palette");
+
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+  yield waitForCondition(() => !navbar.hasAttribute("overflowing"));
+  ok(!navbar.hasAttribute("overflowing"), "Should not have an overflowing toolbar.");
+  let el = document.getElementById(kTestBtn2);
+  if (el) {
+    CustomizableUI.removeWidgetFromArea(kTestBtn2);
+    el.remove();
+  }
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+});
+
+// Constructing a widget while overflown should set the right class on it.
+add_task(function() {
+  originalWindowWidth = window.outerWidth;
+  ok(!navbar.hasAttribute("overflowing"), "Should start with a non-overflowing toolbar.");
+  ok(CustomizableUI.inDefaultState, "Should start in default state.");
+
+  window.resizeTo(400, window.outerHeight);
+  yield waitForCondition(() => navbar.hasAttribute("overflowing"));
+  ok(navbar.hasAttribute("overflowing"), "Should have an overflowing toolbar.");
+  ok(!navbar.querySelector("#" + kHomeBtn), "Home button should no longer be in the navbar");
+  let homeBtnNode = overflowList.querySelector("#" + kHomeBtn);
+  ok(homeBtnNode, "Home button should be overflowing");
+  ok(homeBtnNode && homeBtnNode.getAttribute("overflowedItem") == "true", "Home button should have overflowedItem class");
+
+  let testBtnSpec = {id: kTestBtn3, label: "Overflowable widget test", defaultArea: "nav-bar"};
+  CustomizableUI.createWidget(testBtnSpec);
+  let testNode = overflowList.querySelector("#" + kTestBtn3);
+  ok(testNode, "Test button should be overflowing");
+  ok(testNode && testNode.getAttribute("overflowedItem") == "true", "Test button should have overflowedItem class");
+
+  CustomizableUI.destroyWidget(kTestBtn3);
+  testNode = document.getElementById(kTestBtn3);
+  ok(!testNode, "Test button should be gone");
+
+  CustomizableUI.createWidget(testBtnSpec);
+  testNode = overflowList.querySelector("#" + kTestBtn3);
+  ok(testNode, "Test button should be overflowing");
+  ok(testNode && testNode.getAttribute("overflowedItem") == "true", "Test button should have overflowedItem class");
+
+  CustomizableUI.removeWidgetFromArea(kTestBtn3);
+  testNode = document.getElementById(kTestBtn3);
+  ok(!testNode, "Test button should be gone");
+  CustomizableUI.destroyWidget(kTestBtn3);
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+});
+
+add_task(function asyncCleanup() {
+  window.resizeTo(originalWindowWidth, window.outerHeight);
+  yield resetCustomization();
+});