assertThat(c.asMap().compute("hash-1", (k, v) -> "c")).isEqualTo("c");
    assertThat(c.size()).isEqualTo(1);
    assertThat(c.asMap().computeIfAbsent("hash-2", k -> "")).isEqualTo("");
  }

  public void testComputeIfPresent() {
    cache.put(key, "1");
    // simultaneous update for same key, expect count successful updates
    doParallelCacheOp(count, n -> cache.asMap().computeIfPresent(key, (k, v) -> v + delimiter + n));