assertThat(cache.equals(null)).isFalse();
    }
  }

  public void testEqualsAndHashCode_different() {
    for (CacheBuilder<Object, Object> builder : cacheFactory().buildAllPermutations()) {
      // all caches should be different: instance equality
      new EqualsTester()
          .addEqualityGroup(builder.build(identityLoader()))
          .addEqualityGroup(builder.build(identityLoader()))

  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(), builder -> builder.recordStats().build(identityLoader()));
  }

  private CacheBuilderFactory cacheFactory() {
    // This is trickier than expected. We plan to put 15 values in each of these (WARMUP_MIN to