* that tests equivalence using their lengths:
   *
   * <pre>{@code
   * equiv.wrap("a").equals(equiv.wrap("b")) // true
   * equiv.wrap("a").equals(equiv.wrap("hello")) // false
   * }</pre>
   *
   * <p>Note in particular that an equivalence wrapper is never equal to the object it wraps.
   *
   * <pre>{@code
   * equiv.wrap(obj).equals(obj) // always false
   * }</pre>

   * that tests equivalence using their lengths:
   *
   * <pre>{@code
   * equiv.wrap("a").equals(equiv.wrap("b")) // true
   * equiv.wrap("a").equals(equiv.wrap("hello")) // false
   * }</pre>
   *
   * <p>Note in particular that an equivalence wrapper is never equal to the object it wraps.
   *
   * <pre>{@code
   * equiv.wrap(obj).equals(obj) // always false
   * }</pre>

    ILL_FORMED_STRINGS = builder.build();
  }

  public void testEncodedLength_validStrings() {
    assertEquals(0, Utf8.encodedLength(""));
    assertEquals(11, Utf8.encodedLength("Hello world"));
    assertEquals(8, Utf8.encodedLength("Résumé"));
    assertEquals(
        461,
        Utf8.encodedLength(
            "威廉·莎士比亞（William Shakespeare，"

  }

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

  public void testToStringEmptyIterator() {
    Iterator<String> iterator = Collections.<String>emptyList().iterator();