diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma/String/15.5.4.2-2-n.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma/String/15.5.4.2-2-n.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+/**
+   File Name:          15.5.4.2-2-n.js
+   ECMA Section:       15.5.4.2 String.prototype.toString()
+
+   Description:        Returns this string value.  Note that, for a String
+   object, the toString() method happens to return the same
+   thing as the valueOf() method.
+
+   The toString function is not generic; it generates a
+   runtime error if its this value is not a String object.
+   Therefore it connot be transferred to the other kinds of
+   objects for use as a method.
+
+   Author:             christine@netscape.com
+   Date:               1 october 1997
+*/
+
+var SECTION = "15.5.4.2-3-n";
+var VERSION = "ECMA_1";
+startTest();
+var TITLE   = "String.prototype.toString";
+
+writeHeaderToLog( SECTION + " "+ TITLE);
+
+DESCRIPTION = "var tostr=String.prototype.toString; astring=new Number(); astring.toString = tostr; astring.toString()";
+EXPECTED = "error";
+
+new TestCase( SECTION,
+	      "var tostr=String.prototype.toString; astring=new Number(); astring.toString = tostr; astring.toString()",
+	      "error",
+	      eval("var tostr=String.prototype.toString; astring=new Number(); astring.toString = tostr; astring.toString()") );
+
+test();