fakeTicker.advance(501, MILLISECONDS);

    Set<Integer> foundKeys = new HashSet<>(cache.asMap().keySet());

    assertThat(foundKeys).containsExactly(20, 5);
  }

  @Test
  public void asMapKeySet_contains() {
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder().expireAfterWrite(1000, MILLISECONDS).ticker(fakeTicker).build();

    cache.put(10, 20);
    fakeTicker.advance(500, MILLISECONDS);