if (shouldWait.get()) {
              computingLatch.await();
            }
            return key;
          }
        };
    QueuingRemovalListener<String, String> listener = queuingRemovalListener();

    LoadingCache<String, String> cache =
        CacheBuilder.newBuilder()
            .concurrencyLevel(1)
            .removalListener(listener)

    assertThat(keySet).containsExactly(3, 6);
  }

  public void testExpiration_invalidateAll() {
    FakeTicker ticker = new FakeTicker();
    QueuingRemovalListener<Integer, Integer> listener =
        TestingRemovalListeners.queuingRemovalListener();
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .expireAfterAccess(1, MINUTES)
            .removalListener(listener)