public void testSingletonSetLast() {
    assertEquals(a, sortedSet.last());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a, sortedSet.first());
  }

  @CollectionSize.Require(SEVERAL)
  public void testLast() {
    assertEquals(c, sortedSet.last());
  }

  public void testSingletonMapLast() {
    assertEquals(a.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a.getKey(), navigableMap.firstKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testLast() {
    assertEquals(c.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testHeadMapExclusive() {

  public void testSingletonMapLast() {
    assertEquals(a.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a.getKey(), navigableMap.firstKey());
  }

  @CollectionSize.Require(SEVERAL)
  public void testLast() {
    assertEquals(c.getKey(), navigableMap.lastKey());
  }

  @CollectionSize.Require(absent = ZERO)
  public void testHeadMapExclusive() {

  public void testSingletonMapPollLast() {
    assertEquals(a, navigableMap.pollLastEntry());
    assertTrue(navigableMap.isEmpty());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a, navigableMap.firstEntry());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(SEVERAL)
  public void testPollFirst() {

  }

  public void testFirst() {
    assertEquals(1, ContiguousSet.create(Range.closed(1, 3), integers()).first().intValue());
    assertEquals(1, ContiguousSet.create(Range.open(0, 4), integers()).first().intValue());
    assertEquals(
        Integer.MIN_VALUE,
        ContiguousSet.create(Range.<Integer>all(), integers()).first().intValue());
  }

  public void testLast() {

            .testEquals();
      }
    }
  }

  public abstract static class AbstractFilteredSortedSetTest<C extends SortedSet<Integer>>
      extends AbstractFilteredSetTest<C> {
    public void testFirst() {
      for (List<Integer> contents : SAMPLE_INPUTS) {
        C filtered = filter(createUnfiltered(contents), EVEN);

        try {
          Integer first = filtered.first();

  public void testSingletonMultisetPollLast() {
    assertEquals(a, sortedMultiset.pollLastEntry());
    assertTrue(sortedMultiset.isEmpty());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a, sortedMultiset.firstEntry());
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(SEVERAL)
  public void testPollFirst() {

  }

  public void testFirst() {
    assertEquals(1, ContiguousSet.create(Range.closed(1, 3), integers()).first().intValue());
    assertEquals(1, ContiguousSet.create(Range.open(0, 4), integers()).first().intValue());
    assertEquals(
        Integer.MIN_VALUE,
        ContiguousSet.create(Range.<Integer>all(), integers()).first().intValue());
  }

  public void testLast() {

  public void testSingletonMultisetPollLast() {
    assertEquals(a, sortedMultiset.pollLastEntry());
    assertTrue(sortedMultiset.isEmpty());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {
    assertEquals(a, sortedMultiset.firstEntry());
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(SEVERAL)
  public void testPollFirst() {

  public void testOf_nullPointerException() {
    assertThrows(NullPointerException.class, () -> EquivalenceTester.of(null));
  }

  public void testTest_noData() {
    tester.test();
  }

  public void testTest() {
    Object group1Item1 = new TestObject(1, 1);
    Object group1Item2 = new TestObject(1, 2);
    Object group2Item1 = new TestObject(2, 1);
    Object group2Item2 = new TestObject(2, 2);