}

  public void testCopyOf_iterator_oneElementRepeated() {
    Iterator<String> iterator = Iterators.forArray("a", "a", "a");
    Set<String> set = copyOf(iterator);
    assertEquals(singleton("a"), set);
  }

  public void testCopyOf_iterator_general() {
    Iterator<String> iterator = Iterators.forArray("a", "b", "a");
    Set<String> set = copyOf(iterator);
    assertEquals(2, set.size());

  }

  public void testLeastOfIterator_simple_negativeOne() {
    assertThrows(
        IllegalArgumentException.class,
        () -> numberOrdering.leastOf(Iterators.forArray(3, 4, 5, -1), -1));
  }

  public void testLeastOfIterable_singleton_0() {
    List<Integer> result = numberOrdering.leastOf(asList(3), 0);
    assertTrue(result instanceof RandomAccess);

  }

  public void testLeastOfIterator_simple_negativeOne() {
    assertThrows(
        IllegalArgumentException.class,
        () -> numberOrdering.leastOf(Iterators.forArray(3, 4, 5, -1), -1));
  }

  public void testLeastOfIterable_singleton_0() {
    List<Integer> result = numberOrdering.leastOf(asList(3), 0);
    assertTrue(result instanceof RandomAccess);