* Iterator}, which may be lazily evaluated. If you want an eagerly computed {@link List}, use
   * {@link #splitToList(CharSequence)}. Java 8+ users may prefer {@link #splitToStream} instead.
   *
   * @param sequence the sequence of characters to split
   * @return an iteration over the segments split from the parameter
   */
  public Iterable<String> split(CharSequence sequence) {

    assertThat(letters).containsExactly("a", "b", "c").inOrder();
  }

  public void testCharacterSimpleSplitToStream() {
    String simple = "a,b,c";
    List<String> letters = COMMA_SPLITTER.splitToStream(simple).collect(toImmutableList());
    assertThat(letters).containsExactly("a", "b", "c").inOrder();
  }

  public void testToString() {
    assertThat(COMMA_SPLITTER.split("").toString()).isEqualTo("[]");