emoveChild(video);
                        URL.revokeObjectURL(mediaSourceURL);
                    });

                    mediaSource.addEventListener("sourceopen", test.step_func_done());
                    video.src = mediaSourceURL;
                }, "sourceopen occurs with element preload=" + preload);
            }

            attachWithPreloadTest("auto");
            attachWithPreloadTest("metadata");
            attachWithPreloadTest("none");

            function errorWithPreloadTest(preload,