fakeTicker.advance(501, MILLISECONDS);

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

    assertEquals(ImmutableSet.of(20, 5), foundKeys);
  }

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

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