details-name-closes-other-usecounter.html

<!DOCTYPE html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>

<body>
<div id="group">
  <details name="n" open></details>
  <details name="n"></details>
</div>
<script>

const kHTMLDetailsElementNameAttributeClosesOther = 4679;

test(() => {
  assert_false(internals.isUseCounted(document, kHTMLDetailsElementNameAttributeClosesOther),
               "shouldn't be counted before the test.");

  const e1 = document.querySelector("details[open]");
  const e2 = document.querySelector("details:not([open])");
  assert_true(e1.open, "should be open initially");

  e2.open = true;
  assert_true(internals.isUseCounted(document, kHTMLDetailsElementNameAttributeClosesOther),
              "should be counted after toggling");
  assert_false(e1.open, "should be closed after toggling");
}, 'Behavior of kHTMLDetailsElementNameAttributeClosesOther use counter');

</script>

chromium/third_party/blink/web_tests/html/details_summary/details-name-closes-other-usecounter.html