private static final String KEY_PREFIX = "key prefix:";

  public void testExpiration_expireAfterWrite() {
    FakeTicker ticker = new FakeTicker();
    CountingRemovalListener<String, Integer> removalListener = countingRemovalListener();
    WatchedCreatorLoader loader = new WatchedCreatorLoader();
    LoadingCache<String, Integer> cache =
        CacheBuilder.newBuilder()

    }

    assertEquals(MAX_SIZE, cache.size());
    CacheTesting.checkValidState(cache);
  }

  public void testEviction_maxSize() {
    CountingRemovalListener<Integer, Integer> removalListener = countingRemovalListener();
    IdentityLoader<Integer> loader = identityLoader();
    LoadingCache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .maximumSize(MAX_SIZE)

    assertFalse(CacheBuilder.newBuilder().build().asMap().values() instanceof Set);
  }

  @GwtIncompatible // CacheTesting
  public void testNullCache() {
    CountingRemovalListener<Object, Object> listener = countingRemovalListener();
    LoadingCache<Object, Object> nullCache =
        CacheBuilder.newBuilder().maximumSize(0).removalListener(listener).build(identityLoader());
    assertEquals(0, nullCache.size());

    assertFalse(CacheBuilder.newBuilder().build().asMap().values() instanceof Set);
  }

  @GwtIncompatible // CacheTesting
  public void testNullCache() {
    CountingRemovalListener<Object, Object> listener = countingRemovalListener();
    LoadingCache<Object, Object> nullCache =
        CacheBuilder.newBuilder().maximumSize(0).removalListener(listener).build(identityLoader());
    assertEquals(0, nullCache.size());