* @author George van den Driessche
 */
@GwtIncompatible
public abstract class PerCollectionSizeTestSuiteBuilder<
        B extends PerCollectionSizeTestSuiteBuilder<B, G, T, E>,
        G extends TestContainerGenerator<T, E>,
        T,
        E>
    extends FeatureSpecificTestSuiteBuilder<B, G> {
  private static final Logger logger =
      Logger.getLogger(PerCollectionSizeTestSuiteBuilder.class.getName());

  protected Collection<E> getSampleElements() {
    return getSampleElements(getNumElements());
  }

  /**
   * Returns the {@linkplain #getSampleElements() sample elements} as ordered by {@link
   * TestContainerGenerator#order(List)}. Tests should use this method only if they declare
   * requirement {@link com.google.common.collect.testing.features.CollectionFeature#KNOWN_ORDER}.
   */
  protected List<E> getOrderedElements() {

  static <K extends @Nullable Object, V extends @Nullable Object>
      TestSetGenerator<K> keySetGenerator(
          OneSizeTestContainerGenerator<Map<K, V>, Entry<K, V>> mapGenerator) {
    TestContainerGenerator<Map<K, V>, Entry<K, V>> generator = mapGenerator.getInnerGenerator();
    if (generator instanceof TestSortedMapGenerator
        && ((TestSortedMapGenerator<K, V>) generator).create().keySet() instanceof SortedSet) {