}

  public void testPartition_badSize() {
    Iterator<Integer> source = singletonIterator(1);
    assertThrows(IllegalArgumentException.class, () -> Iterators.partition(source, 0));
  }

  public void testPartition_empty() {
    Iterator<Integer> source = emptyIterator();
    Iterator<List<Integer>> partitions = Iterators.partition(source, 1);
    assertFalse(partitions.hasNext());
  }