mozilla-release/testing/web-platform/tests/feature-policy/reporting/serial-report-only.https.html

<!DOCTYPE html>
<html>
  <head>
    <script src='/resources/testharness.js'></script>
    <script src='/resources/testharnessreport.js'></script>
    <script src='/resources/testdriver.js'></script>
    <script src="/resources/testdriver-vendor.js"></script>
  </head>
  <body>
    <div id='fs'></div>
    <script>
var check_report_format = ([reports, observer]) => {
  let report = reports[0];
  assert_equals(report.type, "feature-policy-violation");
  assert_equals(report.body.featureId, "serial");
  assert_equals(report.body.disposition, "report");
};

promise_test(async t => {
  const report = new Promise(resolve => {
    new ReportingObserver((reports, observer) => resolve([reports, observer]),
                          {types: ['feature-policy-violation']}).observe();
  });

  await test_driver.bless('Activate document for serial.requestPort');
  try {
    await navigator.serial.requestPort({filters: []});
    assert_unreached('requestPort() call should fail when no port is selected.');
  } catch (e) {
    assert_equals(e.code, DOMException.NOT_FOUND_ERR);
  }
  check_report_format(await report);
}, "requestPort in serial report only mode");

promise_test(async t => {
  const report = new Promise(resolve => {
    new ReportingObserver((reports, observer) => resolve([reports, observer]),
                          {types: ['feature-policy-violation']}).observe();
  });

  await navigator.serial.getPorts();
  check_report_format(await report);
}, "getPorts in serial report only mode");
    </script>
  </body>
</html>