}
        };

    List<Integer> toInvalidate = ImmutableList.of(1, 2, 3, 4);
    cache.invalidateAll(toInvalidate);
    assertThat(invalidated).isEqualTo(toInvalidate);
  }

  public void testEmptySimpleStats() {
    StatsCounter counter = new SimpleStatsCounter();
    CacheStats stats = counter.snapshot();
    assertThat(stats.requestCount()).isEqualTo(0);
    assertThat(stats.hitCount()).isEqualTo(0);