.containsExactly(Range.lessThan(3), Range.greaterThan(3))
        .inOrder();
  }

  public void testRemoveMiddle() {
    TreeRangeSet<Integer> rangeSet = TreeRangeSet.create();
    rangeSet.add(Range.atMost(6));
    rangeSet.remove(Range.closedOpen(3, 4));
    testInvariants(rangeSet);
    assertThat(rangeSet.asRanges())
        .containsExactly(Range.lessThan(3), Range.closed(4, 6))
        .inOrder();

    assertEquals(Range.atLeast(Integer.MIN_VALUE), Range.<Integer>all().canonical(integers()));
  }

  public void testCanonical_unboundedDomain() {
    assertEquals(Range.lessThan(0), Range.lessThan(0).canonical(UNBOUNDED_DOMAIN));
    assertEquals(Range.lessThan(1), Range.atMost(0).canonical(UNBOUNDED_DOMAIN));
    assertEquals(Range.atLeast(0), Range.atLeast(0).canonical(UNBOUNDED_DOMAIN));

 * <tr><td>{@code [a..+∞)} <td>{@code {x | x >= a}}     <td>{@link Range#atLeast atLeast}
 * <tr><td>{@code (-∞..b)} <td>{@code {x | x < b}}      <td>{@link Range#lessThan lessThan}
 * <tr><td>{@code (-∞..b]} <td>{@code {x | x <= b}}     <td>{@link Range#atMost atMost}
 * <tr><td>{@code (-∞..+∞)}<td>{@code {x}}              <td>{@link Range#all all}
 * </table>
 *
 * </blockquote>
 *

        @Override
        public long distance(Integer start, Integer end) {
          throw new AssertionError();
        }
      };

  public void testCreate_noMin() {
    Range<Integer> range = Range.lessThan(0);
    assertThrows(
        IllegalArgumentException.class,
        () -> ContiguousSet.create(range, UNBOUNDED_THROWING_DOMAIN));
  }

  public void testCreate_noMax() {

        @Override
        public long distance(Integer start, Integer end) {
          throw new AssertionError();
        }
      };

  public void testCreate_noMin() {
    Range<Integer> range = Range.lessThan(0);
    assertThrows(
        IllegalArgumentException.class,
        () -> ContiguousSet.create(range, UNBOUNDED_THROWING_DOMAIN));
  }

  public void testCreate_noMax() {

    assertEquals(empty, Sets.subSet(set, Range.lessThan(0)));
    assertEquals(ImmutableSortedSet.of(2), Sets.subSet(set, Range.lessThan(4)));
    assertEquals(ImmutableSortedSet.of(2, 4, 6), Sets.subSet(set, Range.lessThan(7)));
    assertEquals(set, Sets.subSet(set, Range.lessThan(20)));

    assertEquals(empty, Sets.subSet(set, Range.atMost(0)));

 * <tr><td>{@code [a..+∞)} <td>{@code {x | x >= a}}     <td>{@link Range#atLeast atLeast}
 * <tr><td>{@code (-∞..b)} <td>{@code {x | x < b}}      <td>{@link Range#lessThan lessThan}
 * <tr><td>{@code (-∞..b]} <td>{@code {x | x <= b}}     <td>{@link Range#atMost atMost}
 * <tr><td>{@code (-∞..+∞)}<td>{@code {x}}              <td>{@link Range#all all}
 * </table>
 *
 * </blockquote>
 *

}

// Validate - validates the filter element
func (f Filter) Validate() error {
	if f.IsEmpty() {
		return errXMLNotWellFormed
	}
	// A Filter must have exactly one of Prefix, Tag,
	// ObjectSize{LessThan,GreaterThan} or And specified.
	type predType uint8
	const (
		nonePred predType = iota
		prefixPred
		andPred
		tagPred
		sizeLtPred
		sizeGtPred
	)
	var predCount int
	var pType predType

//       metadata:
//         - key: content-type
//           value: image/* # match objects with 'content-type', all values starting with 'image/'
//       size:
//         lessThan: "10MiB" # match objects with size less than this value (e.g. 10MiB)
//         greaterThan: 1MiB # match objects with size greater than this value (e.g. 1MiB)
//       purge: