synchronous-callback-skipped-before-run.html

<!DOCTYPE html>
<html>
<title>View transitions: skipTransition() invoked before a synchronous updateDOM callback is invoked</title>
<link rel="help" href="https://www.w3.org/TR/css-view-transitions-1/">
<link rel="author" href="mailto:[email protected]">

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

<style>
div {
  width: 100px;
  height: 100px;
  background: blue;
  contain: paint;
}
</style>

<div id=first></div>

<script>
promise_test(async t => {
  assert_implements(document.startViewTransition, "Missing document.startViewTransition");
  return new Promise(async (resolve, reject) => {
    let transition = document.startViewTransition(() => {
      first.style.viewTransitionName = "target";
    });
    transition.skipTransition();
    await transition.finished;

    if (window.getComputedStyle(first).viewTransitionName == "target")
      resolve();
    else
      reject();
  });
}, "finished promise should be resolved if skipTransition() is invoked before a synchronous updateCallbackDone callback is dispatched");
</script>

chromium/third_party/blink/web_tests/external/wpt/css/css-view-transitions/synchronous-callback-skipped-before-run.html