testOk() {
    expectOk(CUSTOM_MESSAGE);
    mockOkHandler.$replay();
    createAndShow();

    /** @suppress {visibility} suppression added to enable type checking */
    dialog.input_.value = CUSTOM_MESSAGE;
    googTestingEvents.fireClickSequence(dialog.getOkButtonElement());

    mockOkHandler.$verify();  // Verifies OK is dispatched with correct message.
  }
Tests that clicking OK dispatches an event carying the entered message.
@suppress {visibility} suppression added to enable type checking