assertThrows(NoSuchElementException.class, () -> peekingIterator.peek());
    assertThrows(NoSuchElementException.class, () -> peekingIterator.next());
  }

  public void testCantRemoveAfterPeek() {
    List<String> list = Lists.newArrayList("A", "B", "C");
    Iterator<String> iterator = list.iterator();
    PeekingIterator<?> peekingIterator = Iterators.peekingIterator(iterator);