assertTrue(elapsedMillis < timelimitMillis);
  }

  /**
   * Await an interrupt, then clear the interrupt status. Similar to {@code
   * assertTrue(Thread.interrupted())} except that this version tolerates late interrupts.
   */
  private static void assertInterrupted() {
    try {
      /*
       * The sleep() will end immediately if we've already been interrupted or
       * wait patiently for the interrupt if not.

    assertTrue(elapsedMillis < timelimitMillis);
  }

  /**
   * Await an interrupt, then clear the interrupt status. Similar to {@code
   * assertTrue(Thread.interrupted())} except that this version tolerates late interrupts.
   */
  private static void assertInterrupted() {
    try {
      /*
       * The sleep() will end immediately if we've already been interrupted or
       * wait patiently for the interrupt if not.