chromium/third_party/blink/web_tests/html/infrastructure/fallback_base_url.html

<!DOCTYPE html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<body>
<script>
// The specification is unclear for this particular case. We should clarify it
// and merge this test to wpt/html/infrastructure/urls/terminology-0/document-base-url.html

var t = async_test('The fallback base URL of a srcdoc document should be the document base URL of the document\'s browsing context\'s browsing context container\'s document even after the srcdoc document lost its browsing context.');
t.step(() => {
  var iframe = document.createElement('iframe');
  iframe.srcdoc = 'text';
  iframe.onload = t.step_func_done(() => {
    var srcdoc = iframe.contentDocument;
    assert_equals(srcdoc.baseURI, document.baseURI, 'before detaching');
    iframe.remove();
    srcdoc.body.innerHTML = '<base href="relative/">';
    assert_not_equals(srcdoc.baseURI, 'about:srcdoc', 'after detaching');
  });
  document.body.appendChild(iframe);
});
</script>
</body>