diff --git a/dom/apps/tests/file_bug_945152.html b/dom/apps/tests/file_bug_945152.html
index 2c8a09ae0a8..c8485bed4b2 100644
--- a/dom/apps/tests/file_bug_945152.html
+++ b/dom/apps/tests/file_bug_945152.html
@@ -30,7 +30,7 @@
       sendMessage("KO: " + a + " != " + b + " - " + msg);
   }
 
-  function testXHR(file, data_head, mapped, cb) {
+  function check_XHR(file, data_head, mapped, cb) {
     var xhr = new XMLHttpRequest();
     xhr.open('GET', file);
     xhr.responseType = 'arraybuffer';
@@ -60,19 +60,57 @@
     xhr.send();
   }
 
+  function check_XHR_mapped(file, cb) {
+    var xhr = new XMLHttpRequest();
+    xhr.open('GET', file);
+    xhr.responseType = 'arraybuffer';
+    xhr.onreadystatechange = function xhrReadystatechange() {
+      if (xhr.readyState !== xhr.DONE) {
+        return;
+      }
+      if (xhr.status && xhr.status == 200) {
+        var ct = xhr.getResponseHeader("Content-Type");
+        cb(ct.indexOf("mem-mapped") != -1);
+      } else {
+        cb(false);
+      }
+    }
+    xhr.send();
+  }
+
+  // Reading multiple mapped array buffer by XHR simultaneously
+  function test_simultaneous() {
+    var count = 0;
+    var num = 100;
+    var succeed = true;
+    function cb(result) {
+      if (!result) {
+        succeed = false;
+      }
+      if (++count == num) {
+        ok(succeed, "Succeeded on simultaneous access test");
+        runTests();
+      }
+    }
+    for (var i = 0; i < num; i++) {
+      check_XHR_mapped('data_1.txt', cb);
+    }
+  }
+
   // Memory-mapped array buffer.
   function test_mapped() {
-    testXHR('data_1.txt', gData1, true, runTests);
+    check_XHR('data_1.txt', gData1, true, runTests);
   }
 
   // Non memory-mapped array buffer.
   function test_non_mapped() {
     // Make sure array buffer retrieved from compressed file in package is
     // handled by memory allocation instead of memory mapping.
-    testXHR('data_2.txt', gData2, false, runTests);
+    check_XHR('data_2.txt', gData2, false, runTests);
   }
 
   var tests = [
+    test_simultaneous,
     test_mapped,
     test_non_mapped
   ];