}
        final StringBuilder sb = new StringBuilder(s);
        int i;
        for (i = 0; i < sb.length() - 1; i++) {
            final char originalChar1 = sb.charAt(i);
            final char originalChar2 = sb.charAt(i + 1);
            final char margedChar = mergeChar(originalChar1, originalChar2);
            if (margedChar != originalChar1) {
                sb.setCharAt(i, margedChar);

    scratch.putLong(l);
    return update(scratch, Longs.BYTES);
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putChar(char c) {
    ByteBuffer scratch = scratch();
    scratch.putChar(c);
    return update(scratch, Chars.BYTES);
  }

  private ByteBuffer scratch() {
    if (scratch == null) {
      scratch = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN);
    }

    String expected = begin + end;
    assertEquals(expected.charAt(0), joinedReader.read());
    CharStreams.skipFully(joinedReader, 1);
    assertEquals(expected.charAt(2), joinedReader.read());
    CharStreams.skipFully(joinedReader, 4);
    assertEquals(expected.charAt(7), joinedReader.read());
    CharStreams.skipFully(joinedReader, 1);
    assertEquals(expected.charAt(9), joinedReader.read());
    assertEquals(-1, joinedReader.read());

        // Test extended ASCII characters (not valid URL chars without encoding)
        assertFalse(CharUtil.isUrlChar('\u00A0')); // non-breaking space
        assertFalse(CharUtil.isUrlChar('\u00FF')); // ÿ
    }

    public void test_isUrlChar_unicode() {
        // Test Unicode characters (not valid URL chars without encoding)
        assertFalse(CharUtil.isUrlChar('\u3042')); // あ (Hiragana)

    public static final String MIN_ELEMENT = "a";
    public static final String AFTER_LAST = "z";
    public static final String AFTER_LAST_2 = "zz";
  }

  public static class Chars extends SampleElements<Character> {
    public Chars() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super('b', 'a', 'c', 'd', 'e');
    }
  }

  public static class Enums extends SampleElements<AnEnum> {

  }

  public void testFlatteningToImmutableListMultimap() {
    Collector<String, ?, ImmutableListMultimap<Character, Character>> collector =
        flatteningToImmutableListMultimap(
            str -> str.charAt(0), str -> Chars.asList(str.substring(1).toCharArray()).stream());
    BiPredicate<Multimap<?, ?>, Multimap<?, ?>> equivalence =
        Equivalence.equals()

    for (String edge : edges) {
      checkArgument(
          edge.length() == 2, "Expecting each edge to consist of 2 characters but got %s", edge);
      char node1 = edge.charAt(0);
      char node2 = edge.charAt(1);
      graphMapBuilder.put(node1, node2);
      if (!directed) {
        graphMapBuilder.put(node2, node1);
      }
    }

    }
  }

  public void testUtf8() {
    char[] charsA = new char[128];
    char[] charsB = new char[128];

    for (int i = 0; i < charsA.length; i++) {
      if (i < 100) {
        charsA[i] = 'a';
        charsB[i] = 'a';
      } else {
        // Both two-byte characters, but must be different
        charsA[i] = (char) (0x0180 + i);
        charsB[i] = (char) (0x0280 + i);
      }
    }

    }
  }

  public void testUtf8() {
    char[] charsA = new char[128];
    char[] charsB = new char[128];

    for (int i = 0; i < charsA.length; i++) {
      if (i < 100) {
        charsA[i] = 'a';
        charsB[i] = 'a';
      } else {
        // Both two-byte characters, but must be different
        charsA[i] = (char) (0x0180 + i);
        charsB[i] = (char) (0x0280 + i);
      }
    }

        }
      }
    }
    if (ipString.charAt(0) == IPV6_DELIMITER && ipString.charAt(1) != IPV6_DELIMITER) {
      return null; // ^: requires ^::
    }
    if (ipString.charAt(ipString.length() - 1) == IPV6_DELIMITER
        && ipString.charAt(ipString.length() - 2) != IPV6_DELIMITER) {
      return null; // :$ requires ::$
    }