chromium/src/third_party/blink/web_tests/external/wpt/permissions-policy/resources/permissions-policy-clipboard-write.html

<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script>
'use strict';

(async () => {
  try {
    // TODO(https://crbug.com/1074482): Cross-origin focus is asynchronous and
    // requires user gesture. Implement testing support for cross-origin focus.
    window.focus(); // The Clipboard API requires focus.

    await test_driver.set_permission({ name: 'clipboard-write' }, 'granted');
    await navigator.clipboard.writeText('test text');

    window.parent.postMessage({ enabled: true }, "*");
  } catch (e) {
    window.parent.postMessage({ enabled: false }, "*");
  }
})();
</script>