Helpers.addAll(elements, previousElements);
      Helpers.addAll(elements, Helpers.reverse(nextElements));
      return elements;
    }
  }

  public enum KnownOrder {
    KNOWN_ORDER,
    UNKNOWN_ORDER
  }

  @SuppressWarnings("unchecked") // TODO(cpovirk): Stop using arrays.
  AbstractIteratorTester(
      int steps,
      Iterable<E> elementsToInsertIterable,

      Helpers.addAll(elements, previousElements);
      Helpers.addAll(elements, Helpers.reverse(nextElements));
      return elements;
    }
  }

  public enum KnownOrder {
    KNOWN_ORDER,
    UNKNOWN_ORDER
  }

  @SuppressWarnings("unchecked") // TODO(cpovirk): Stop using arrays.
  AbstractIteratorTester(
      int steps,
      Iterable<E> elementsToInsertIterable,

      builder.append("FAILURE, cause=[").append(e.getCause()).append("]");
    } catch (CancellationException e) {
      builder.append("CANCELLED");
    } catch (RuntimeException e) {
      builder.append("UNKNOWN, cause=[").append(e.getClass()).append(" thrown from get()]");
    }
  }

  private enum State {
    PENDING {
      @Override
      boolean isDone() {
        return false;
      }

 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available
 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no
 *       value" (present in the map, with value {@code Optional.absent()})
 *   <li>To wrap nullable references for storage in a collection that does not support {@code null}

    IteratorTester<T> tester =
        new IteratorTester<T>(
            steps,
            IteratorFeature.MODIFIABLE,
            Lists.newLinkedList(values),
            IteratorTester.KnownOrder.UNKNOWN_ORDER) {
          private @Nullable MinMaxPriorityQueue<T> mmHeap;

          @Override
          protected Iterator<T> newTargetIterator() {
            mmHeap = MinMaxPriorityQueue.create(values);

    }
    return returnValue;
  }

  /**
   * Thrown if the test tries to invoke a constructor or static factory method but failed because
   * the dummy value of a constructor or method parameter is unknown.
   */
  @VisibleForTesting
  static class ParameterNotInstantiableException extends Exception {
    public ParameterNotInstantiableException(Parameter parameter) {
      super(

 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available
 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no
 *       value" (present in the map, with value {@code Optional.absent()})
 *   <li>To wrap nullable references for storage in a collection that does not support {@code null}

                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(new DegeneratedImmutableSetGenerator())
            .named(ImmutableSetTest.class.getName() + ", degenerate")
            .withFeatures(
                CollectionSize.ONE,
                CollectionFeature.KNOWN_ORDER,

    CollectionSize.ANY, CollectionFeature.KNOWN_ORDER, CollectionFeature.ALLOWS_NULL_QUERIES
  };

  private static final Feature<?>[] COLLECTION_FEATURES_REMOVE = {
    CollectionSize.ANY, CollectionFeature.SUPPORTS_REMOVE, CollectionFeature.ALLOWS_NULL_QUERIES
  };

  private static final Feature<?>[] COLLECTION_FEATURES_REMOVE_ORDER = {
    CollectionSize.ANY,
    CollectionFeature.KNOWN_ORDER,
    CollectionFeature.SUPPORTS_REMOVE,

                  }
                })
            .named("Maps.transformValues[Map, Function]")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,
                MapFeature.ALLOWS_NULL_KEYS,
                MapFeature.ALLOWS_ANY_NULL_QUERIES,
                MapFeature.SUPPORTS_REMOVE,
                CollectionFeature.SUPPORTS_ITERATOR_REMOVE)