diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/Array/regress-315509-01.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/Array/regress-315509-01.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,28 @@
+/* -*- 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 = 315509;
+var summary = 'Array.prototype.unshift on Arrays with holes';
+var actual = '';
+var expect = '';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+var a = [0,1,2,3,4];
+delete a[1];
+
+expect = '0,,2,3,4';
+actual = a.toString();
+
+reportCompare(expect, actual, summary);
+
+a.unshift('a','b');
+
+expect = 'a,b,0,,2,3,4';
+actual = a.toString();
+ 
+reportCompare(expect, actual, summary);