return standardDescendingKeySet();
    }

    @Override
    public K firstKey() {
      return standardFirstKey();
    }

    @Override
    public SortedMap<K, V> headMap(K toKey) {
      return standardHeadMap(toKey);
    }

    @Override
    public K lastKey() {
      return standardLastKey();
    }

    @Override
    public SortedMap<K, V> tailMap(K fromKey) {

      assertEquals(
          ImmutableMap.of('a', ImmutableMap.of(1, "foo", 2, "baz"), 'b', ImmutableMap.of(1, "bar")),
          testInstance.rowMap());
    }
  }

      }
    }

    @Override
    public NavigableMap<K, V> headMap(K toKey, boolean inclusive) {
      synchronized (mutex) {
        return navigableMap(delegate().headMap(toKey, inclusive), mutex);
      }
    }

    @Override
    public SortedMap<K, V> headMap(K toKey) {
      return headMap(toKey, false);
    }

    @Override
    @CheckForNull

      populateTable(table);
      return table.rowMap();
    }

    void populateTable(Table<String, Integer, Character> table) {
      table.put("foo", 1, 'a');
      table.put("bar", 1, 'b');
      table.put("foo", 3, 'c');
    }

    @Override
    protected Map<String, Map<Integer, Character>> makeEmptyMap() {
      return makeTable().rowMap();
    }
  }

    SortedMap<String, Integer> headMap = map.headMap("a");
    assertTrue(headMap instanceof SynchronizedSortedMap);
    assertSame(mutex, ((SynchronizedSortedMap<String, Integer>) headMap).mutex);
  }

  public void testHeadMap_K_B() {
    NavigableMap<String, Integer> map = create();
    NavigableMap<String, Integer> headMap = map.headMap("a", true);
    assertTrue(headMap instanceof SynchronizedNavigableMap);

    }
  }

  @Override
  @CheckForNull
  public Entry<K, V> lowerEntry(@ParametricNullness K key) {
    return headMap(key, false).lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<K, V> floorEntry(@ParametricNullness K key) {
    return headMap(key, true).lastEntry();
  }

  @Override
  @CheckForNull
  public Entry<K, V> ceilingEntry(@ParametricNullness K key) {

     */
    SortedMap<K, V> createSubMap(SortedMap<K, V> map, K firstExclusive, K lastExclusive) {
      if (from == Bound.NO_BOUND && to == Bound.EXCLUSIVE) {
        return map.headMap(lastExclusive);
      } else if (from == Bound.INCLUSIVE && to == Bound.NO_BOUND) {
        return map.tailMap(firstInclusive);
      } else if (from == Bound.INCLUSIVE && to == Bound.EXCLUSIVE) {

    Set<Integer> treeValues = ImmutableSet.of(4, 0);
    assertEquals(ImmutableMap.of("google", googleValues, "tree", treeValues), asMap.tailMap("g"));
    assertEquals(ImmutableMap.of("google", googleValues, "foo", fooValues), asMap.headMap("h"));
    assertEquals(ImmutableMap.of("google", googleValues), asMap.subMap("g", "h"));
  }

  public void testTailSetClear() {
    TreeMultimap<String, Integer> multimap = TreeMultimap.create();

    assertEquals(Integer.valueOf(4), map.get("four"));
    SortedMap<String, Integer> headMap = map.headMap("two");
    assertEquals(ImmutableSortedMap.of("four", 4, "one", 3, "three", 5), headMap);
    strings.add("five");
    strings.remove("one");
    assertEquals(ImmutableSortedMap.of("five", 4, "four", 4, "three", 5), headMap);
    assertThat(map.entrySet())
        .containsExactly(

    assertEquals(Integer.valueOf(4), map.get("four"));
    SortedMap<String, Integer> headMap = map.headMap("two");
    assertEquals(ImmutableSortedMap.of("four", 4, "one", 3, "three", 5), headMap);
    strings.add("five");
    strings.remove("one");
    assertEquals(ImmutableSortedMap.of("five", 4, "four", 4, "three", 5), headMap);
    assertThat(map.entrySet())
        .containsExactly(