diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_group.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_group.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,111 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function test() {
+  waitForExplicitFinish();
+
+  showTabView(onTabViewWindowLoaded);
+}
+
+let originalGroupItem = null;
+let originalTab = null;
+
+function onTabViewWindowLoaded() {
+  ok(TabView.isVisible(), "Tab View is visible");
+
+  let contentWindow = TabView.getContentWindow();
+
+  is(contentWindow.GroupItems.groupItems.length, 1, "There is one group item on startup");
+  originalGroupItem = contentWindow.GroupItems.groupItems[0];
+  is(originalGroupItem.getChildren().length, 1, "There should be one Tab Item in that group.");
+  contentWindow.UI.setActive(originalGroupItem);
+
+  [originalTab] = gBrowser.visibleTabs;
+
+  testEmptyGroupItem(contentWindow);
+}
+
+function testEmptyGroupItem(contentWindow) {
+  let groupItemCount = contentWindow.GroupItems.groupItems.length;
+  
+  // create empty group item
+  let emptyGroupItem = createEmptyGroupItem(contentWindow, 300, 300, 100);
+  ok(emptyGroupItem.isEmpty(), "This group is empty");
+
+  is(contentWindow.GroupItems.groupItems.length, ++groupItemCount,
+     "The number of groups is increased by 1");
+
+  emptyGroupItem.addSubscriber("close", function onClose() {
+    emptyGroupItem.removeSubscriber("close", onClose);
+
+    // check the number of groups.
+    is(contentWindow.GroupItems.groupItems.length, --groupItemCount,
+       "The number of groups is decreased by 1");
+
+    testGroupItemWithTabItem(contentWindow);
+  });
+
+  let closeButton = emptyGroupItem.container.getElementsByClassName("close");
+  ok(closeButton[0], "Group close button exists");
+
+  // click the close button
+  EventUtils.synthesizeMouse(closeButton[0], 1, 1, {}, contentWindow);
+}
+
+function testGroupItemWithTabItem(contentWindow) {
+  let groupItem = createEmptyGroupItem(contentWindow, 300, 300, 200);
+  let tabItemCount = 0;
+
+  let onTabViewShown = function() {
+    let tabItem = groupItem.getChild(groupItem.getChildren().length - 1);
+    ok(tabItem, "Tab item exists");
+
+    let tabItemClosed = false;
+    tabItem.addSubscriber("close", function onClose() {
+      tabItem.removeSubscriber("close", onClose);
+      tabItemClosed = true;
+    });
+    tabItem.addSubscriber("tabRemoved", function onTabRemoved() {
+      tabItem.removeSubscriber("tabRemoved", onTabRemoved);
+
+      ok(tabItemClosed, "The tab item is closed");
+      is(groupItem.getChildren().length, --tabItemCount,
+        "The number of children in new tab group is decreased by 1");
+
+      ok(TabView.isVisible(), "Tab View is still shown");
+
+      // Now there should only be one tab left, so we need to hide TabView
+      // and go into that tab.
+      is(gBrowser.tabs.length, 1, "There is only one tab left");
+
+      // after the last selected tabitem is closed, there would be not active
+      // tabitem on the UI so we set the active tabitem before toggling the 
+      // visibility of tabview
+      let tabItems = contentWindow.TabItems.getItems();
+      ok(tabItems[0], "A tab item exists");
+      contentWindow.UI.setActive(tabItems[0]);
+
+      hideTabView(function() {
+        ok(!TabView.isVisible(), "Tab View is hidden");
+
+        closeGroupItem(groupItem, finish);
+      });
+    });
+
+    // remove the tab item.  The code detects mousedown and mouseup so we stimulate here
+    let closeButton = tabItem.container.getElementsByClassName("close");
+    ok(closeButton, "Tab item close button exists");
+
+    EventUtils.sendMouseEvent({ type: "mousedown" }, closeButton[0], contentWindow);
+    EventUtils.sendMouseEvent({ type: "mouseup" }, closeButton[0], contentWindow);
+  };
+
+  whenTabViewIsHidden(function() {
+    is(groupItem.getChildren().length, ++tabItemCount,
+       "The number of children in new tab group is increased by 1");
+
+    ok(!TabView.isVisible(), "Tab View is hidden because we just opened a tab");
+    showTabView(onTabViewShown);
+  });
+  groupItem.newTab();
+}