* 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));
  }

  /**

    // Now we don't care what order it's put the list in, only that
    // comparing any pair of elements gives the answer we expect.
    testComparator(arbitrary, list);
  }

  public void testUsingToString() {
    Ordering<Object> ordering = Ordering.usingToString();
    testComparator(ordering, 1, 12, 124, 2);
    assertThat(ordering.toString()).isEqualTo("Ordering.usingToString()");

    // Now we don't care what order it's put the list in, only that
    // comparing any pair of elements gives the answer we expect.
    testComparator(arbitrary, list);
  }

  public void testUsingToString() {
    Ordering<Object> ordering = Ordering.usingToString();
    testComparator(ordering, 1, 12, 124, 2);
    assertThat(ordering.toString()).isEqualTo("Ordering.usingToString()");

                MapFeature.ALLOWS_NULL_VALUES,
                CollectionFeature.SUPPORTS_ITERATOR_REMOVE)
            .createTestSuite());

    return suite;
  }

  public void testComparator() {
    assertThat(create().comparator()).isNotNull();
  }

  public void testCeilingEntry() {
    assertThat(create().ceilingEntry("a")).isNull();
  }

  public void testCeilingKey() {

    Comparator<byte[]> comparator = UnsignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
    assertThat(SerializableTester.reserialize(comparator)).isSameInstanceAs(comparator);

    // The Java implementation.
    Comparator<byte[]> javaImpl = UnsignedBytes.lexicographicalComparatorJavaImpl();
    Helpers.testComparator(javaImpl, ordered);

    Comparator<byte[]> comparator = UnsignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
    assertThat(SerializableTester.reserialize(comparator)).isSameInstanceAs(comparator);

    // The Java implementation.
    Comparator<byte[]> javaImpl = UnsignedBytes.lexicographicalComparatorJavaImpl();
    Helpers.testComparator(javaImpl, ordered);

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

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

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

            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});

            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});

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

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

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