// An 8n+{1,3,6} length string is never legal base32.
    assertFailsToDecode(base32(), "A", "Invalid input length 1");
    assertFailsToDecode(base32(), "ABC");
    assertFailsToDecode(base32(), "ABCDEF");
    // These have a combination of invalid length, unrecognized characters and wrong padding.
    assertFailsToDecode(base32(), "AB=C", "Unrecognized character: =");

    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));
    assertEquals("abc", Strings.commonPrefix(new StringBuilder("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(
        "abc\uD8AB\uDCAB", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCABxyz"));
    // Differing valid surrogate pairs.

    // An 8n+{1,3,6} length string is never legal base32.
    assertFailsToDecode(base32(), "A", "Invalid input length 1");
    assertFailsToDecode(base32(), "ABC");
    assertFailsToDecode(base32(), "ABCDEF");
    // These have a combination of invalid length, unrecognized characters and wrong padding.
    assertFailsToDecode(base32(), "AB=C", "Unrecognized character: =");

    Iterable<String> letters = Splitter.fixedLength(2).split(simple);
    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() {