assertEquals("foobar", Ascii.toLowerCase("fOobaR"));
  }

  public void testToUpperCase() {
    assertEquals(UPPER, Ascii.toUpperCase(LOWER));
    assertSame(UPPER, Ascii.toUpperCase(UPPER));
    assertEquals(IGNORED, Ascii.toUpperCase(IGNORED));
    assertEquals("FOOBAR", Ascii.toUpperCase("FoOBAr"));
  }

  public void testCharsIgnored() {
    for (char c : IGNORED.toCharArray()) {
      String str = String.valueOf(c);

   * without modification.
   *
   * @since 14.0
   */
  public static String toUpperCase(CharSequence chars) {
    if (chars instanceof String) {
      return toUpperCase((String) chars);
    }
    char[] newChars = new char[chars.length()];
    for (int i = 0; i < newChars.length; i++) {
      newChars[i] = toUpperCase(chars.charAt(i));
    }
    return String.valueOf(newChars);
  }

  /**

    @Override
    String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },

  /** C++ variable naming convention, e.g., "lower_underscore". */
  LOWER_UNDERSCORE(CharMatcher.is('_'), "_") {
    @Override

  }

  @Benchmark
  int asciiStringToUpperCase(int reps) {
    String string = noWorkToDo ? Ascii.toUpperCase(testString) : testString;

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += Ascii.toUpperCase(string).length();
    }
    return dummy;
  }

  @Benchmark
  int asciiCharSequenceToUpperCase(int reps) {

    assertEquals("foobar", Ascii.toLowerCase("fOobaR"));
  }

  public void testToUpperCase() {
    assertEquals(UPPER, Ascii.toUpperCase(LOWER));
    assertSame(UPPER, Ascii.toUpperCase(UPPER));
    assertEquals(IGNORED, Ascii.toUpperCase(IGNORED));
    assertEquals("FOOBAR", Ascii.toUpperCase("FoOBAr"));
  }

  public void testCharsIgnored() {
    for (char c : IGNORED.toCharArray()) {
      String str = String.valueOf(c);

      BaseEncoding encoding, String decoded, String encoded) {
    testEncodingWithSeparators(encoding, decoded, encoded);
    testEncodingWithSeparators(encoding.upperCase(), decoded, Ascii.toUpperCase(encoded));
    testEncodingWithSeparators(encoding.lowerCase(), decoded, Ascii.toLowerCase(encoded));
  }

  private static void testEncodingWithSeparators(

    @Override
    String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },

  /** C++ variable naming convention, e.g., "lower_underscore". */
  LOWER_UNDERSCORE(CharMatcher.is('_'), "_") {
    @Override

  }

  @Benchmark
  int asciiStringToUpperCase(int reps) {
    String string = noWorkToDo ? Ascii.toUpperCase(testString) : testString;

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += Ascii.toUpperCase(string).length();
    }
    return dummy;
  }

  @Benchmark
  int asciiCharSequenceToUpperCase(int reps) {

   * <p>Consider normalizing your string references with {@link #nullToEmpty}. If you do, you can
   * use {@link String#isEmpty()} instead of this method, and you won't need special null-safe forms
   * of methods like {@link String#toUpperCase} either. Or, if you'd like to normalize "in the other
   * direction," converting empty strings to {@code null}, you can use {@link #emptyToNull}.
   *
   * @param string a string reference to check

          // Canonical escaper method that only escapes lower case ASCII letters.
          @Override
          protected char @Nullable [] escape(int cp) {
            return ('a' <= cp && cp <= 'z') ? new char[] {Character.toUpperCase((char) cp)} : null;
          }
          // Inefficient implementation that defines all letters as escapable.
          @Override
          protected int nextEscapeIndex(CharSequence csq, int index, int end) {