diff -r 000000000000 -r 6474c204b198 browser/components/tabview/test/browser_tabview_rtl.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/tabview/test/browser_tabview_rtl.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/ */
+
+// ----------
+function test() {
+  waitForExplicitFinish();
+
+  // verify initial state
+  ok(!TabView.isVisible(), "Tab View starts hidden");
+
+  showTabView(onTabViewLoadedAndShown("ltr"));
+}
+
+// ----------
+function onTabViewLoadedAndShown(dir) {
+  return function() {
+    ok(TabView.isVisible(), "Tab View is visible.");
+
+    let contentWindow = document.getElementById("tab-view").contentWindow;
+    let contentDocument = contentWindow.document;
+    is(contentDocument.documentElement.getAttribute("dir"), dir,
+       "The direction should be set to " + dir.toUpperCase());
+
+    // kick off the series
+    hideTabView(onTabViewHidden(dir));
+  };
+}
+
+// ---------- 
+function onTabViewHidden(dir) {
+  return function() {
+    ok(!TabView.isVisible(), "Tab View is hidden.");
+
+    if (dir == "ltr") {
+      // Switch to RTL mode
+      Services.prefs.setCharPref("intl.uidirection.en-US", "rtl");
+
+      showTabView(onTabViewLoadedAndShown("rtl"));
+    } else {
+      // Switch to LTR mode
+      Services.prefs.clearUserPref("intl.uidirection.en-US");
+
+      finish();
+    }
+  };
+}