Iterator<String> iterator = Lists.newArrayList("yam", "bam", "jam", "ham").iterator();
    assertEquals("[yam, bam, jam, ham]", Iterators.toString(iterator));
  }

  public void testToStringWithNull() {
    Iterator<@Nullable String> iterator =
        Lists.<@Nullable String>newArrayList("hello", null, "world").iterator();
    assertEquals("[hello, null, world]", Iterators.toString(iterator));
  }