}));
    assertThat(cache.getIfPresent(key)).isEqualTo("1");
    assertThat(cache.asMap().computeIfPresent(key, (k, v) -> "2")).isEqualTo("2");
  }

  public void testUpdates() {
    cache.put(key, "1");
    // simultaneous update for same key, some null, some non-null
    doParallelCacheOp(
        count, n -> cache.asMap().compute(key, (k, v) -> n % 2 == 0 ? v + delimiter + n : null));