CacheBuilder.newBuilder().expireAfterWrite(Duration.ofHours(1));
    assertThrows(IllegalStateException.class, () -> builder.expireAfterWrite(Duration.ofHours(1)));
  }

  public void testTimeToIdle_negative() {
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder();
    assertThrows(IllegalArgumentException.class, () -> builder.expireAfterAccess(-1, SECONDS));
  }

  @GwtIncompatible // Duration