public void testPollLastUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableSet.pollLast());
  }

  @CollectionSize.Require(SEVERAL)
  public void testDescendingNavigation() {
    List<E> descending = new ArrayList<>();
    for (Iterator<E> i = navigableSet.descendingIterator(); i.hasNext(); ) {
      descending.add(i.next());
    }
    Collections.reverse(descending);

  public void testPollLastUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableSet.pollLast());
  }

  @CollectionSize.Require(SEVERAL)
  public void testDescendingNavigation() {
    List<E> descending = new ArrayList<>();
    for (Iterator<E> i = navigableSet.descendingIterator(); i.hasNext(); ) {
      descending.add(i.next());
    }
    Collections.reverse(descending);

  public void testPollLastUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableMap.pollLastEntry());
  }

  @CollectionSize.Require(SEVERAL)
  public void testDescendingNavigation() {
    List<Entry<K, V>> descending = new ArrayList<>(navigableMap.descendingMap().entrySet());
    Collections.reverse(descending);
    assertEquals(entries, descending);
  }