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()))

  CacheBuilderFactory withValueStrengths(Set<Strength> valueStrengths) {
    this.valueStrengths = new LinkedHashSet<>(valueStrengths);
    return this;
  }

  Iterable<CacheBuilder<Object, Object>> buildAllPermutations() {
    Iterable<List<Object>> combinations =
        buildCartesianProduct(
            concurrencyLevels,
            initialCapacities,
            maximumSizes,
            expireAfterWrites,

  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(
        factory.buildAllPermutations(), builder -> builder.build(KEY_TO_STRING_LOADER));
  }

  public void testContainsKeyAndValue() {
    for (LoadingCache<Key, String> cache : caches()) {

  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(
        factory.buildAllPermutations(), builder -> builder.build(KEY_TO_STRING_LOADER));
  }

  public void testContainsKeyAndValue() {
    for (LoadingCache<Key, String> cache : caches()) {

  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