}
        };

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

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