1 files changed, 48 insertions, 0 deletions
diff --git a/dom/tests/mochitest/bugs/test_bug848088.html b/dom/tests/mochitest/bugs/test_bug848088.html
new file mode 100644
index 0000000000..24c43c421a
--- /dev/null
+++ b/dom/tests/mochitest/bugs/test_bug848088.html
@@ -0,0 +1,48 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=848088
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 848088</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+  <script type="application/javascript">
+
+  /** Test for Bug 848088 **/
+
+function test(loopFor, setExpandoAt)
+{
+    var list = document.getElementsByTagName("audio");
+    delete list.length;
+    var shouldHaveExpando = false;
+    var realLength = list.length;
+    for (var i = 0; i < loopFor; ++i) {
+        if (i == setExpandoAt) {
+            // Add an expando that shadows.
+            Object.defineProperty(list, "length", { value: "a" });
+            shouldHaveExpando = true;
+        }
+        var hasExpando = (list.length != realLength);
+        if (shouldHaveExpando != hasExpando) {
+            return false;
+        }
+    }
+    return true;
+}
+
+ok(test(200000, 100000), "Correctly detected expando on DOM list object");
+
+ </script>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=848088">Mozilla Bug 848088</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+</html>