chromium/src/third_party/blink/web_tests/external/wpt/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/012-1.html

<script>
onload = parent.t.step_func(function() {
  parent.assert_equals(document.open(), document);
  setTimeout(parent.t.step_func(function() {parent.t.done()}), 0);
  document.close();
});
</script>