assertSame(Ordering.natural(), copyFromSorted.valueComparator());
    assertSame(Ordering.natural(), copyFromSorted.get(1.0).comparator());
  }

  public void testComparators() {
    TreeMultimap<String, Integer> multimap = TreeMultimap.create();
    assertEquals(Ordering.natural(), multimap.keyComparator());
    assertEquals(Ordering.natural(), multimap.valueComparator());
  }

   * the given {@code comparator}.
   *
   * @see #testComparator(Comparator, List)
   */
  public static <T extends @Nullable Object> void testComparator(
      Comparator<? super T> comparator, T... valuesInExpectedOrder) {
    testComparator(comparator, asList(valuesInExpectedOrder));
  }

  /**

            new byte[] {GREATEST, GREATEST},
            new byte[] {GREATEST, GREATEST, GREATEST});

    Comparator<byte[]> comparator = SignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {

            new byte[] {GREATEST, GREATEST},
            new byte[] {GREATEST, GREATEST, GREATEST});

    Comparator<byte[]> comparator = SignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {

            new long[] {GREATEST, GREATEST},
            new long[] {GREATEST, GREATEST, GREATEST});

    Comparator<long[]> comparator = UnsignedLongs.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  public void testSort() {
    testSort(new long[] {}, new long[] {});
    testSort(new long[] {2}, new long[] {2});
    testSort(new long[] {2, 1, 0}, new long[] {0, 1, 2});

    TreeMultimap<@Nullable String, @Nullable Integer> multimap = createPopulate();
    assertThat(multimap.values()).containsExactly(7, 3, 1, null, 0, 6, 2).inOrder();
  }

  public void testComparator() {
    TreeMultimap<@Nullable String, @Nullable Integer> multimap = createPopulate();
    assertEquals(DECREASING_INT_COMPARATOR, multimap.get("foo").comparator());

            new char[] {GREATEST, GREATEST},
            new char[] {GREATEST, GREATEST, GREATEST});

    Comparator<char[]> comparator = Chars.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {

            new double[] {GREATEST, GREATEST},
            new double[] {GREATEST, GREATEST, GREATEST});

    Comparator<double[]> comparator = Doubles.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  public void testReverse() {
    testReverse(new double[] {}, new double[] {});
    testReverse(new double[] {1}, new double[] {1});

            new int[] {GREATEST, GREATEST},
            new int[] {GREATEST, GREATEST, GREATEST});

    Comparator<int[]> comparator = Ints.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {

            new boolean[] {true, false},
            new boolean[] {true, true},
            new boolean[] {true, true, true});

    Comparator<boolean[]> comparator = Booleans.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {