diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_exit_button.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_exit_button.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,92 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+let contentWindow;
+let appTab;
+let originalTab;
+let exitButton;
+
+// ----------
+function test() {
+  waitForExplicitFinish();
+
+  window.addEventListener("tabviewshown", onTabViewLoadedAndShown, false);
+  TabView.toggle();
+}
+
+// ----------
+function onTabViewLoadedAndShown() {
+  window.removeEventListener("tabviewshown", onTabViewLoadedAndShown, false);
+  ok(TabView.isVisible(), "Tab View is visible");
+
+  contentWindow = document.getElementById("tab-view").contentWindow;
+
+  // establish initial state
+  is(contentWindow.GroupItems.groupItems.length, 1,
+      "we start with one group (the default)");
+  is(gBrowser.tabs.length, 1, "we start with one tab");
+  originalTab = gBrowser.tabs[0];
+  ok(!originalTab.pinned, "the original tab is not an app tab");
+
+  // create an app tab
+  appTab = gBrowser.loadOneTab("about:blank");
+  is(gBrowser.tabs.length, 2, "we now have two tabs");
+  gBrowser.pinTab(appTab);
+
+  // verify that the normal tab is selected
+  ok(originalTab.selected, "the normal tab is selected");
+
+  // hit the exit button for the first time
+  exitButton = contentWindow.document.getElementById("exit-button");
+  ok(exitButton, "Exit button exists");
+
+  window.addEventListener("tabviewhidden", onTabViewHiddenForNormalTab, false);
+  EventUtils.sendMouseEvent({ type: "click" }, exitButton, contentWindow);
+}
+
+// ----------
+function onTabViewHiddenForNormalTab() {
+  window.removeEventListener("tabviewhidden", onTabViewHiddenForNormalTab, false);
+  ok(!TabView.isVisible(), "Tab View is not visible");
+
+  // verify that the normal tab is still selected
+  ok(originalTab.selected, "the normal tab is still selected");
+
+  // select the app tab
+  gBrowser.selectedTab = appTab;
+  ok(appTab.selected, "the app tab is now selected");
+
+  // go back to tabview
+  window.addEventListener("tabviewshown", onTabViewShown, false);
+  TabView.toggle();
+}
+
+// ----------
+function onTabViewShown() {
+  window.removeEventListener("tabviewshown", onTabViewShown, false);
+  ok(TabView.isVisible(), "Tab View is visible");
+
+  // hit the exit button again
+  window.addEventListener("tabviewhidden", onTabViewHiddenForAppTab, false);
+  EventUtils.sendMouseEvent({ type: "click" }, exitButton, contentWindow);
+}
+
+// ----------
+function onTabViewHiddenForAppTab() {
+  window.removeEventListener("tabviewhidden", onTabViewHiddenForAppTab, false);
+  ok(!TabView.isVisible(), "Tab View is not visible");
+
+  // verify that the app tab is still selected
+  ok(appTab.selected, "the app tab is still selected");
+
+  // clean up
+  gBrowser.selectedTab = originalTab;
+  gBrowser.removeTab(appTab);
+
+  is(gBrowser.tabs.length, 1, "we finish with one tab");
+  ok(originalTab.selected,
+      "we finish with the normal tab selected");
+  ok(!TabView.isVisible(), "we finish with Tab View not visible");
+
+  finish();
+}