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

<!DOCTYPE html>
<html>
  <head>
    <script src='/resources/testharness.js'></script>
    <script src='/resources/testharnessreport.js'></script>
  </head>
  <body>
    <script>
var check_report_format = ([reports, observer]) => {
  let report = reports[0];
  assert_equals(report.type, "feature-policy-violation");
  assert_equals(report.body.featureId, "geolocation");
  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();
  });
  try {
    await new Promise((resolve, reject) => {
      navigator.geolocation.getCurrentPosition(resolve, reject);
    });
    check_report_format(await report);
  } catch (err) {
    // In case the getCurrentPosition call was rejected due to user permissions,
    // the report should be generated anyway. Wait for it and check the format
    // before failing this test.
    check_report_format(await report);
    throw err;
  }
}, "Geolocation report only mode");
    </script>
  </body>
</html>