* actual implementation tests are further down.
   */

  public abstract static class AbstractFilteredIterableTest<C extends Iterable<Integer>>
      extends TestCase {
    abstract C createUnfiltered(Iterable<Integer> contents);

    abstract C filter(C elements, Predicate<? super Integer> predicate);

    public void testIterationOrderPreserved() {

      @Override
      public UnmodifiableIterator<E> iterator() {
        Iterable<E> incidentEdges =
            (selfLoopCount == 0)
                ? Iterables.concat(inEdgeMap.keySet(), outEdgeMap.keySet())
                : Sets.union(inEdgeMap.keySet(), outEdgeMap.keySet());
        return Iterators.unmodifiableIterator(incidentEdges.iterator());
      }

      @Override
      public int size() {

        verify(tree, times(1)).acquire();
        verify(tree, times(1)).release();
    }

    @Test
    @DisplayName("Happy path: iterates entries, fetchMore(), then closes with FindClose2")
    void iteratesAndFetchesMoreThenCloses() throws Exception {
        // Arrange: program send() to simulate first, next, next(NO_MORE_FILES)

HSPLkotlin/sequences/ConstrainedOnceSequence;->iterator()Ljava/util/Iterator;
HSPLkotlin/sequences/SequencesKt;->toList(Lkotlin/sequences/Sequence;)Ljava/util/List;
HSPLkotlin/sequences/SequencesKt__SequencesKt$asSequence$$inlined$Sequence$1;-><init>(Ljava/util/Iterator;)V
HSPLkotlin/sequences/SequencesKt__SequencesKt$asSequence$$inlined$Sequence$1;->iterator()Ljava/util/Iterator;

  /**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {

  /**
   * A sensible definition of {@link #pollFirstEntry} in terms of the {@code iterator} of {@code
   * entrySet}. If you override {@code entrySet}, you may wish to override {@code pollFirstEntry} to
   * forward to this implementation.
   */
  protected @Nullable Entry<K, V> standardPollFirstEntry() {
    return Iterators.pollNext(entrySet().iterator());
  }

  @Override
  public @Nullable Entry<K, V> pollLastEntry() {

      iterator.remove();
    }
  }

  /** ValueIterator build on top of EntryIterator. */
  final class ValueIterator implements Iterator<V> {
    private EntryIterator iterator;

    ValueIterator() {
      iterator = new EntryIterator();
    }

    @Override
    public boolean hasNext() {
      return iterator.hasNext();
    }

    @Override
    public V next() {

            Currency.PESO, Country.CHILE,
            Currency.FRANC, Country.SWITZERLAND);
    EnumBiMap<Currency, Country> bimap = EnumBiMap.create(map);

    Iterator<Currency> iter = bimap.keySet().iterator();
    assertEquals(Currency.DOLLAR, iter.next());
    iter.remove();

    // forward map ordered by currency
    assertThat(bimap.keySet()).containsExactly(Currency.FRANC, Currency.PESO).inOrder();

   * (`implements Function<@PolyNull A, @PolyNull B>`), at least as far as I know.)
   */
  public Iterable<B> convertAll(Iterable<? extends A> fromIterable) {
    checkNotNull(fromIterable, "fromIterable");
    return () ->
        new Iterator<B>() {
          private final Iterator<? extends A> fromIterator = fromIterable.iterator();

          @Override
          public boolean hasNext() {

  /**
   * Returns a view of this range map as an unmodifiable {@code Map<Range<K>, V>}. Modifications to
   * this range map are guaranteed to read through to the returned {@code Map}.
   *
   * <p>The returned {@code Map} iterates over entries in ascending order of the bounds of the
   * {@code Range} entries.
   *
   * <p>It is guaranteed that no empty ranges will be in the returned {@code Map}.
   */
  Map<Range<K>, V> asMapOfRanges();