diff --git a/js/tests/js1_5/Array/regress-315509-01.js b/js/tests/js1_5/Array/regress-315509-01.js
new file mode 100755
index 000000000000..ae9046f6b667
--- /dev/null
+++ b/js/tests/js1_5/Array/regress-315509-01.js
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is JavaScript Engine testing utilities.
+ *
+ * The Initial Developer of the Original Code is
+ * Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2005
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s): moz_bug_r_a4
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+//-----------------------------------------------------------------------------
+var bug = 315509;
+var summary = 'Array.prototype.unshift on Arrays with holes';
+var actual = '';
+var expect = '';
+
+printBugNumber (bug);
+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);
diff --git a/js/tests/js1_5/Array/regress-315509-02.js b/js/tests/js1_5/Array/regress-315509-02.js
new file mode 100755
index 000000000000..df298d80399b
--- /dev/null
+++ b/js/tests/js1_5/Array/regress-315509-02.js
@@ -0,0 +1,73 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is JavaScript Engine testing utilities.
+ *
+ * The Initial Developer of the Original Code is
+ * Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2005
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s): moz_bug_r_a4
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+//-----------------------------------------------------------------------------
+var bug = 315509;
+var summary = 'Array.prototype.unshift do not crash on Arrays with holes';
+var actual = 'No Crash';
+var expect = 'No Crash';
+
+printBugNumber (bug);
+printStatus (summary);
+
+function x1() {
+	var a = new Array(1);
+	a.unshift(1);
+}
+function x2() {
+	var a = new Array(1);
+	a.unshift.call(a, 1);
+}
+function x3() {
+	var a = new Array(1);
+	a.x = a.unshift;
+	a.x(1);
+}
+function x4() {
+	var a = new Array(1);
+	a.__defineSetter__("x", a.unshift);
+	a.x = 1;
+}
+
+for (var i = 0; i < 10; i++)
+{
+  x1();
+  x2();
+  x3();
+  x4();
+}
+  
+reportCompare(expect, actual, summary);