*/
  private static final SuccessorsFunction<Character> MULTI_GRAPH =
      createDirectedGraph("aa", "dd", "ab", "ac", "ca", "cd", "bd");

  /** A directed graph with a single cycle: a -> b -> c -> d -> a. */
  private static final SuccessorsFunction<Character> CYCLE_GRAPH =
      createDirectedGraph("ab", "bc", "cd", "da");

  /**
   * Same as {@link #CYCLE_GRAPH}, but with an extra a->c edge.
   *
   * <pre>{@code

   */
  private static final SuccessorsFunction<Character> MULTI_GRAPH =
      createDirectedGraph("aa", "dd", "ab", "ac", "ca", "cd", "bd");

  /** A directed graph with a single cycle: a -> b -> c -> d -> a. */
  private static final SuccessorsFunction<Character> CYCLE_GRAPH =
      createDirectedGraph("ab", "bc", "cd", "da");

  /**
   * Same as {@link #CYCLE_GRAPH}, but with an extra a->c edge.
   *
   * <pre>{@code

    assertThat(letters).containsExactly("ab", "cd", "e").inOrder();
  }

  public void testFixedLengthSplitEqualChunkLength() {
    String simple = "abcdef";
    Iterable<String> letters = Splitter.fixedLength(2).split(simple);
    assertThat(letters).containsExactly("ab", "cd", "ef").inOrder();
  }

  public void testFixedLengthSplitOnlyOneChunk() {

    assertThat(letters).containsExactly("ab", "cd", "e").inOrder();
  }

  public void testFixedLengthSplitEqualChunkLength() {
    String simple = "abcdef";
    Iterable<String> letters = Splitter.fixedLength(2).split(simple);
    assertThat(letters).containsExactly("ab", "cd", "ef").inOrder();
  }

  public void testFixedLengthSplitOnlyOneChunk() {

  }

  /**
   * Returns a splitter that divides strings into pieces of the given length. For example, {@code
   * Splitter.fixedLength(2).split("abcde")} returns an iterable containing {@code ["ab", "cd",
   * "e"]}. The last piece can be smaller than {@code length} but will never be empty.
   *
   * <p><b>Note:</b> if {@link #fixedLength} is used in conjunction with {@link #limit}, the final

  }

  /**
   * Returns a splitter that divides strings into pieces of the given length. For example, {@code
   * Splitter.fixedLength(2).split("abcde")} returns an iterable containing {@code ["ab", "cd",
   * "e"]}. The last piece can be smaller than {@code length} but will never be empty.
   *
   * <p><b>Note:</b> if {@link #fixedLength} is used in conjunction with {@link #limit}, the final