firefox/testing/web-platform/tests/speech-api/SpeechRecognition-onerror.https.html

<!DOCTYPE html>
<title>SpeechRecognition onerror event</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
  promise_test(async t => {
  window.SpeechRecognition = window.SpeechRecognition || window.webkitSpeechRecognition;
  const recognition = new SpeechRecognition();

  // Promise that resolves when the 'error' event is fired.
  const errorPromise = new Promise(resolve => {
    recognition.onerror = (event) => {
      resolve();
    };
  });

  // Start speech recognition.
  recognition.start();

  // Wait for the 'error' event.
  await errorPromise;

  // Stop speech recognition.
  recognition.stop();
}, 'Speech recognition onerror event is called.');
</script>