ImmutableMap<Range<Integer>, Integer> descendingMap = rangeMap.asDescendingMapOfRanges();
          assertEquals(expectedAsMap, asMap);
          assertEquals(expectedAsMap, descendingMap);
          SerializableTester.reserializeAndAssert(asMap);
          SerializableTester.reserializeAndAssert(descendingMap);
          assertEquals(
              ImmutableList.copyOf(asMap.entrySet()).reverse(),

  }

  public void testDescendingMap() {
    NavigableMap<String, Integer> map = create();
    NavigableMap<String, Integer> descendingMap = map.descendingMap();
    assertTrue(descendingMap instanceof SynchronizedNavigableMap);
    assertSame(mutex, ((SynchronizedNavigableMap<String, Integer>) descendingMap).mutex);
  }

  public void testFirstEntry() {
    create().firstEntry();
  }

  public void testFirstKey() {

          ImmutableMap<Range<Integer>, Integer> descendingMap = rangeMap.asDescendingMapOfRanges();
          assertEquals(expectedAsMap, asMap);
          assertEquals(expectedAsMap, descendingMap);
          SerializableTester.reserializeAndAssert(asMap);
          SerializableTester.reserializeAndAssert(descendingMap);
          assertEquals(
              ImmutableList.copyOf(asMap.entrySet()).reverse(),

  @Override
  public ImmutableSortedMap<K, V> descendingMap() {
    // TODO(kevinb): The descendingMap is never actually cached at all. Either:
    //
    // - Cache it, and annotate the field with @LazyInit.
    // - Simplify the code below, and consider eliminating the field (b/287198172), which is also
    //   set by one of the constructors.
    ImmutableSortedMap<K, V> result = descendingMap;
    if (result == null) {

        assertThat(navigableMap.headMap(key, inclusive).descendingMap().entrySet())
            .containsExactlyElementsIn(expected.headMap(key, inclusive).descendingMap().entrySet())
            .inOrder();
        assertThat(navigableMap.tailMap(key, inclusive).descendingMap().entrySet())
            .containsExactlyElementsIn(expected.tailMap(key, inclusive).descendingMap().entrySet())
            .inOrder();
      }
    }
  }

    }

    @LazyInit @CheckForNull private transient UnmodifiableNavigableMap<K, V> descendingMap;

    @Override
    public NavigableMap<K, V> descendingMap() {
      UnmodifiableNavigableMap<K, V> result = descendingMap;
      return (result == null)
          ? descendingMap = new UnmodifiableNavigableMap<>(delegate.descendingMap(), this)
          : result;
    }

    @Override

    }

    @LazyInit @CheckForNull private transient UnmodifiableNavigableMap<K, V> descendingMap;

    @Override
    public NavigableMap<K, V> descendingMap() {
      UnmodifiableNavigableMap<K, V> result = descendingMap;
      return (result == null)
          ? descendingMap = new UnmodifiableNavigableMap<>(delegate.descendingMap(), this)
          : result;
    }

    @Override

  @Override
  public ImmutableSortedMap<K, V> descendingMap() {
    // TODO(kevinb): The descendingMap is never actually cached at all. Either:
    //
    // - Cache it, and annotate the field with @LazyInit.
    // - Simplify the code below, and consider eliminating the field (b/287198172), which is also
    //   set by one of the constructors.
    ImmutableSortedMap<K, V> result = descendingMap;
    if (result == null) {

      super(delegate);
    }

    @Override
    public NavigableMap<K, V> create(Object... entries) {
      NavigableMap<K, V> map = (NavigableMap<K, V>) delegate.create(entries);
      return map.descendingMap();
    }

    @Override
    public Iterable<Entry<K, V>> order(List<Entry<K, V>> insertionOrder) {
      insertionOrder = castOrCopyToList(delegate.order(insertionOrder));
      reverse(insertionOrder);

      }
    }

    @CheckForNull transient NavigableMap<K, V> descendingMap;

    @Override
    public NavigableMap<K, V> descendingMap() {
      synchronized (mutex) {
        if (descendingMap == null) {
          return descendingMap = navigableMap(delegate().descendingMap(), mutex);
        }
        return descendingMap;
      }
    }

    @Override
    @CheckForNull