rchParams;
  setup({ single_test: true });
  // Waiting exercises the case where a user prompt appears while waiting for
  // the next testdriver event. The WebDriver-specified behavior is to resolve
  // with `null` [1, 2], which the WebDriver executor should ignore. The
  // testdriver event loop will handle the open prompt on its next cycle. For
  // the default "dismiss and notify" handler, this throws an unexpected alert
  // open error in the executor.
  //
  // [1]: Step 5.3 of https://www.w3.org/TR/