ThreadFactory factory1 = builder.setPriority(1).build();
    assertEquals(1, factory1.newThread(monitoredRunnable).getPriority());

    ThreadFactory factory2 = builder.setPriority(2).build();
    assertEquals(1, factory1.newThread(monitoredRunnable).getPriority());
    assertEquals(2, factory2.newThread(monitoredRunnable).getPriority());
  }

  public void testBuildTwice() {
    ThreadFactory unused;

    ThreadFactory factory1 = builder.setPriority(1).build();
    assertEquals(1, factory1.newThread(monitoredRunnable).getPriority());

    ThreadFactory factory2 = builder.setPriority(2).build();
    assertEquals(1, factory1.newThread(monitoredRunnable).getPriority());
    assertEquals(2, factory2.newThread(monitoredRunnable).getPriority());
  }

  public void testBuildTwice() {
    ThreadFactory unused;

   *
   * @param priority the priority for new Threads created with this ThreadFactory
   * @return this for the builder pattern
   */
  @CanIgnoreReturnValue
  public ThreadFactoryBuilder setPriority(int priority) {
    // Thread#setPriority() already checks for validity. These error messages
    // are nicer though and will fail-fast.
    checkArgument(
        priority >= Thread.MIN_PRIORITY,

    // Sleep for enough time to add 1500 milliseconds of overwait to the get() call.
    long toWaitMillis = 3500 - TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - thread.startTime);
    Thread.sleep(toWaitMillis);
    thread.setPriority(Thread.MAX_PRIORITY);
    thread.resume();
    thread.join();
    // It's possible to race and suspend the thread just before the park call actually takes effect,

    // Sleep for enough time to add 1500 milliseconds of overwait to the get() call.
    long toWaitMillis = 3500 - TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - thread.startTime);
    Thread.sleep(toWaitMillis);
    thread.setPriority(Thread.MAX_PRIORITY);
    thread.resume();
    thread.join();
    // It's possible to race and suspend the thread just before the park call actually takes effect,