rangeSet.add(range);

      TreeRangeSet<Integer> complement = TreeRangeSet.create();
      complement.add(Range.<Integer>all());
      complement.remove(range);

      assertEquals(complement, rangeSet.complement());
      assertThat(rangeSet.complement().asRanges())
          .containsExactlyElementsIn(complement.asRanges())
          .inOrder();
    }
  }

    this(ranges, /* complement= */ null);
  }

  private ImmutableRangeSet(
      ImmutableList<Range<C>> ranges, @Nullable ImmutableRangeSet<C> complement) {
    this.ranges = ranges;
    this.complement = complement;
  }

  private final transient ImmutableList<Range<C>> ranges;
  private final transient @Nullable ImmutableRangeSet<C> complement;

  @Override

    } else {
      rangesByLowerBound.put(range.lowerBound, range);
    }
  }

  @LazyInit private transient @Nullable RangeSet<C> complement;

  @Override
  public RangeSet<C> complement() {
    RangeSet<C> result = complement;
    return (result == null) ? complement = new Complement() : result;
  }

  @VisibleForTesting
  static final class RangesByUpperBound<C extends Comparable<?>>

      }

      ImmutableRangeSet<Integer> built = builder.build();
      assertEquals(mutable, built);
      assertEquals(ImmutableRangeSet.copyOf(mutable), built);
      assertEquals(mutable.complement(), built.complement());

      for (int i = 0; i <= 11; i++) {
        assertEquals(mutable.contains(i), built.contains(i));
      }

      SerializableTester.reserializeAndAssert(built);

    this(ranges, /* complement= */ null);
  }

  private ImmutableRangeSet(
      ImmutableList<Range<C>> ranges, @Nullable ImmutableRangeSet<C> complement) {
    this.ranges = ranges;
    this.complement = complement;
  }

  private final transient ImmutableList<Range<C>> ranges;
  private final transient @Nullable ImmutableRangeSet<C> complement;

  @Override

   * @since 19.0
   */
  Set<Range<C>> asDescendingSetOfRanges();

  /**
   * Returns a view of the complement of this {@code RangeSet}.
   *
   * <p>The returned view supports the {@link #add} operation if this {@code RangeSet} supports
   * {@link #remove}, and vice versa.
   */
  RangeSet<C> complement();

  /**
   * Returns a view of the intersection of this {@code RangeSet} with the specified range.
   *

@NullUnmarked
public abstract class AbstractRangeSetTest extends TestCase {
  public static void testInvariants(RangeSet<?> rangeSet) {
    testInvariantsInternal(rangeSet);
    testInvariantsInternal(rangeSet.complement());
  }

  private static <C extends Comparable<?>> void testInvariantsInternal(RangeSet<C> rangeSet) {
    assertEquals(rangeSet.asRanges().isEmpty(), rangeSet.isEmpty());

@NullUnmarked
public abstract class AbstractRangeSetTest extends TestCase {
  public static void testInvariants(RangeSet<?> rangeSet) {
    testInvariantsInternal(rangeSet);
    testInvariantsInternal(rangeSet.complement());
  }

  private static <C extends Comparable<?>> void testInvariantsInternal(RangeSet<C> rangeSet) {
    assertEquals(rangeSet.asRanges().isEmpty(), rangeSet.isEmpty());

        assertNotNull(zeroAvFlags, "AvFlags object should not be null for zero bytes");
        assertEquals(0, zeroAvFlags.getFlags(), "Flags should be 0 for zero bytes");

        // Test with negative integer (two's complement)
        byte[] negativeBytes = new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0xFF }; // Represents -1
        AvFlags negativeAvFlags = new AvFlags(negativeBytes);

   * @since 19.0
   */
  Set<Range<C>> asDescendingSetOfRanges();

  /**
   * Returns a view of the complement of this {@code RangeSet}.
   *
   * <p>The returned view supports the {@link #add} operation if this {@code RangeSet} supports
   * {@link #remove}, and vice versa.
   */
  RangeSet<C> complement();

  /**
   * Returns a view of the intersection of this {@code RangeSet} with the specified range.
   *