diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_bug612470.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_bug612470.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,46 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Tests that groups behave properly when closing all tabs but app tabs.
+
+function test() {
+  let cw, win, groupItem;
+
+  let onLoad = function (tvwin) {
+    win = tvwin;
+    registerCleanupFunction(function () win.close());
+    win.gBrowser.pinTab(win.gBrowser.tabs[0]);
+    win.gBrowser.loadOneTab("about:blank", {inBackground: true});
+  };
+
+  let onShow = function () {
+    cw = win.TabView.getContentWindow();
+    is(cw.GroupItems.groupItems.length, 1, "There's only one group");
+
+    groupItem = createEmptyGroupItem(cw, 200, 200, 20);
+    cw.UI.setActive(groupItem);
+
+    whenTabViewIsHidden(onHide, win);
+    cw.UI.goToTab(win.gBrowser.tabs[0]);
+  };
+
+  let onHide = function () {
+    let tab = win.gBrowser.loadOneTab("about:blank", {inBackground: true});
+    is(groupItem.getChildren().length, 1, "One tab is in the new group");
+
+    executeSoon(function () {
+      is(win.gBrowser.visibleTabs.length, 2, "There are two tabs displayed");
+      win.gBrowser.removeTab(tab);
+
+      is(groupItem.getChildren().length, 0, "No tabs are in the new group");
+      is(win.gBrowser.visibleTabs.length, 1, "There is one tab displayed");
+      is(cw.GroupItems.groupItems.length, 2, "There are two groups still");
+
+      finish();
+    });
+  };
+
+  waitForExplicitFinish();
+
+  newWindowWithTabView(onShow, onLoad);
+}