assertThat(keySet).containsExactly(3, 6);
  }

  public void testExpiration_invalidateAll() {
    FakeTicker ticker = new FakeTicker();
    QueuingRemovalListener<Integer, Integer> listener =
        TestingRemovalListeners.queuingRemovalListener();
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .expireAfterAccess(1, MINUTES)
            .removalListener(listener)