createCacheBuilder().maximumSize(SMALL_MAX_SIZE),
        createCacheBuilder().expireAfterAccess(99999, SECONDS),
        createCacheBuilder().expireAfterWrite(99999, SECONDS),
        createCacheBuilder()
            .maximumSize(SMALL_MAX_SIZE)
            .expireAfterAccess(SMALL_MAX_SIZE, TimeUnit.SECONDS),
        createCacheBuilder()
            .maximumSize(SMALL_MAX_SIZE)

        return "Predicates.alwaysFalse()";
      }
    },
    /** @see Predicates#isNull() */
    IS_NULL {
      @Override
      public boolean apply(@CheckForNull Object o) {
        return o == null;
      }

      @Override
      public String toString() {
        return "Predicates.isNull()";
      }
    },
    /** @see Predicates#notNull() */
    NOT_NULL {
      @Override

    } catch (NumberFormatException expected) {
    }
  }

  public void testStringConverter_nullConversions() {
    assertThat(Doubles.stringConverter().convert(null)).isNull();
    assertThat(Doubles.stringConverter().reverse().convert(null)).isNull();
  }

  @GwtIncompatible // Double.toString returns different value in GWT.
  public void testStringConverter_reverse() {

    } catch (NumberFormatException expected) {
    }
  }

  public void testStringConverter_nullConversions() {
    assertThat(Doubles.stringConverter().convert(null)).isNull();
    assertThat(Doubles.stringConverter().reverse().convert(null)).isNull();
  }

  @GwtIncompatible // Double.toString returns different value in GWT.
  public void testStringConverter_reverse() {

      T key = keysAndValues[i];
      T value = keysAndValues[i + 1];
      T old = map.put(key, value);
      assertWithMessage("Key %s set to %s and %s", key, value, old).that(old).isNull();
    }
    return map;
  }

  private static <T extends @Nullable Object> Entry<T, T> entry(T key, T value) {
    return new AbstractMap.SimpleImmutableEntry<>(key, value);
  }

  // Timed Get
  // There are a few design constraints to consider
  // * We want to be responsive to small timeouts, unpark() has non trivial latency overheads (I
  //   have observed 12 micros on 64-bit linux systems to wake up a parked thread). So if the
  //   timeout is small we shouldn't park(). This needs to be traded off with the cpu overhead of

  }

  public void testImmediateVoidFuture() throws Exception {
    ListenableFuture<@Nullable Void> voidFuture = immediateVoidFuture();

    assertThat(getDone(voidFuture)).isNull();
    assertThat(getDoneFromTimeoutOverload(voidFuture)).isNull();
    assertThat(voidFuture.toString()).contains("[status=SUCCESS, result=[null]]");
  }

  public void testImmediateFailedFuture() throws Exception {

    Random random = new Random(0);
    Multiset<Integer> elements = HashMultiset.create();
    MinMaxPriorityQueue<Integer> queue = MinMaxPriorityQueue.create();
    int range = 10_000; // range should be small enough that equal elements occur semi-frequently
    for (int iter = 0; iter < reduceIterationsIfGwt(1000); iter++) {
      for (int i = 0; i < 100; i++) {
        Integer element = random.nextInt(range);

   *     new ImmutableMap.Builder<String, Integer>()
   *         .put("one", 1)
   *         .put("two", 2)
   *         .put("three", 3)
   *         .buildOrThrow();
   * }</pre>
   *
   * <p>For <i>small</i> immutable maps, the {@code ImmutableMap.of()} methods are even more
   * convenient.
   *
   * <p>By default, a {@code Builder} will generate maps that iterate over entries in the order they

   *         .put(1, "one")
   *         .put(2, "two")
   *         .put(3, "three")
   *         .buildOrThrow();
   * }</pre>
   *
   * <p>For <i>small</i> immutable sorted maps, the {@code ImmutableSortedMap.of()} methods are even
   * more convenient.
   *
   * <p>Builder instances can be reused - it is safe to call {@link #buildOrThrow} multiple times to