diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_3/Statements/12.6.3.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_3/Statements/12.6.3.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,47 @@
+/* -*- 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/. */
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 292731;
+var summary = 'for-in should not call valueOf method';
+var actual = '';
+var expect = '';
+var i;
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+function MyObject()
+{
+}
+
+MyObject.prototype.valueOf = function()
+{
+  actual += 'MyObject.prototype.valueOf called. ';
+}
+
+  var myobject = new MyObject();
+
+var myfunction = new function()
+{
+  this.valueOf = function()
+  {
+    actual += 'this.valueOf called. ';
+  }
+}
+
+  actual = '';
+for (i in myobject)
+{
+  //calls valueOf
+}
+reportCompare(expect, actual, 'for-in custom object');
+
+actual = '';
+for (i in myfunction)
+{
+  //calls valueOf
+}
+reportCompare(expect, actual, 'for-in function expression');