first-party-cookie-accepted.https.html

<!DOCTYPE html>
<meta charset="utf-8"/>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/websockets/cookies/support/websocket-cookies-helper.sub.js"></script>
<script>
if (window.testRunner) {
  // Block third-party cookies.
  testRunner.setBlockThirdPartyCookies(true);
}

promise_test(() => {
  var value = '' + Math.random();
  var origin = WSS_ORIGIN;
  return setSameSiteCookies(origin, value).then(
    () => connectAndGetRequestCookiesFrom(origin)
  ).then(
    cookies => {
      assert_not_equals(cookies, '(none)', 'request should contain cookies.');
      assertCookie(cookies, 'samesite-unspecified', value, true /* present */);
      assertCookie(cookies, 'samesite-lax', value, true /* present */);
      assertCookie(cookies, 'samesite-strict', value, true /* present */);
      assertCookie(cookies, 'samesite-none', value, true /* present */);
      return clearSameSiteCookies(origin);
    }
  );
}, 'Test that first-party cookies are not blocked for WebSockets.');
</script>

chromium/third_party/blink/web_tests/wpt_internal/websocket-cookies/first-party-cookie-accepted.https.html