diff -r 000000000000 -r 6474c204b198 js/src/tests/test262/intl402/ch12/12.1/12.1.2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/test262/intl402/ch12/12.1/12.1.2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+// Copyright 2011-2012 Norbert Lindenberg. All rights reserved.
+// Copyright 2012 Mozilla Corporation. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/**
+ * @description Tests that Intl.DateTimeFormat can be subclassed.
+ * @author Norbert Lindenberg
+ */
+
+$INCLUDE("testIntl.js");
+
+// get a date-time format and have it format an array of dates for comparison with the subclass
+var locales = ["tlh", "id", "en"];
+var a = [new Date(0), Date.now(), new Date(Date.parse("1989-11-09T17:57:00Z"))];
+var referenceDateTimeFormat = new Intl.DateTimeFormat(locales);
+var referenceFormatted = a.map(referenceDateTimeFormat.format);
+
+function MyDateTimeFormat(locales, options) {
+    Intl.DateTimeFormat.call(this, locales, options);
+    // could initialize MyDateTimeFormat properties
+}
+
+MyDateTimeFormat.prototype = Object.create(Intl.DateTimeFormat.prototype);
+MyDateTimeFormat.prototype.constructor = MyDateTimeFormat;
+// could add methods to MyDateTimeFormat.prototype
+
+var format = new MyDateTimeFormat(locales);
+var actual = a.map(format.format);
+testArraysAreSame(referenceFormatted, actual);
+