("test", "readwrite")
                          .objectStore("test")
                          .index("index")
                          .openCursor();

        cursor_rq.onsuccess = t.step_func(function(e) {
            var cursor = e.target.result;
            assert_true(cursor instanceof IDBCursor);

            var record = cursor.value;
            record.data = document;
            assert_throws_dom('DataCloneError', function() {
                cursor.update(record);
            });
            t.d