private static final String UPPER = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

  public void testToLowerCase() {
    assertEquals(LOWER, Ascii.toLowerCase(UPPER));
    assertSame(LOWER, Ascii.toLowerCase(LOWER));
    assertEquals(IGNORED, Ascii.toLowerCase(IGNORED));
    assertEquals("foobar", Ascii.toLowerCase("fOobaR"));
  }

  public void testToUpperCase() {
    assertEquals(UPPER, Ascii.toUpperCase(LOWER));

    }

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

  private final CharMatcher wordBoundary;
  private final String wordSeparator;

    public static final String OS_NAME = System.getProperty("os.name").toLowerCase(Locale.ENGLISH);

    /**
     * The OA architecture.
     */
    public static final String OS_ARCH = System.getProperty("os.arch").toLowerCase(Locale.ENGLISH);

    /**
     * The OS version.
     */
    public static final String OS_VERSION = System.getProperty("os.version").toLowerCase(Locale.ENGLISH);

    /**
     * OS Family
     */

                .toLowerCase(Locale.ENGLISH);
        String actualOsArch = context.getSystemProperties()
                .getOrDefault("os.arch", Os.OS_ARCH)
                .toLowerCase(Locale.ENGLISH);
        String actualOsVersion = context.getSystemProperties()
                .getOrDefault("os.version", Os.OS_VERSION)
                .toLowerCase(Locale.ENGLISH);

    }

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

  private final CharMatcher wordBoundary;
  private final String wordSeparator;

        return System.getProperty("os.name").toLowerCase(Locale.ROOT).contains("windows");
    }

    private static boolean isMacOS() {
        return System.getProperty("os.name").toLowerCase(Locale.ROOT).contains("mac");
    }

    private static boolean isAlpine() {
        return System.getProperty("java.vm.vendor").toLowerCase(Locale.ROOT).contains("alpine");
    }

        }
    }

    private void parseHtmlEntity(StringBuilder buffer) {
        scanner.next();
        scanner.mark();
        scanner.find(';');
        String value = ENTITIES.get(scanner.region().toLowerCase(Locale.ROOT));
        buffer.append(value);
        scanner.next();
    }

    private void parseHtmlEncodedChar(StringBuilder buffer) {
        scanner.next(2);
        scanner.mark();

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

  /**

  @JvmField val name: ByteString,
  /** Value in UTF-8 encoding. */
  @JvmField val value: ByteString,
) {
  @JvmField val hpackSize = 32 + name.size + value.size

  // TODO: search for toLowerCase and consider moving logic here.
  constructor(name: String, value: String) : this(name.encodeUtf8(), value.encodeUtf8())

  constructor(name: ByteString, value: String) : this(name, value.encodeUtf8())

  public void testGetKeyMatchesString() {
    for (StandardSystemProperty property : StandardSystemProperty.values()) {
      String fieldName = property.name();
      String expected = Ascii.toLowerCase(fieldName).replaceAll("_", ".");
      assertEquals(expected, property.key());
    }
  }

  public void testGetValue() {
    for (StandardSystemProperty property : StandardSystemProperty.values()) {