assertFalse(str, Ascii.isUpperCase(c));
    }
  }

  public void testCharsLower() {
    for (char c : LOWER.toCharArray()) {
      String str = String.valueOf(c);
      assertTrue(str, c == Ascii.toLowerCase(c));
      assertFalse(str, c == Ascii.toUpperCase(c));
      assertTrue(str, Ascii.isLowerCase(c));
      assertFalse(str, Ascii.isUpperCase(c));
    }
  }

  public void testCharsUpper() {

  @Deprecated
  public static CharMatcher javaLetterOrDigit() {
    return JavaLetterOrDigit.INSTANCE;
  }

  /**
   * Determines whether a BMP character is upper case according to {@linkplain
   * Character#isUpperCase(char) Java's definition}.
   *
   * @deprecated Some uppercase characters are supplementary characters; see the class
   *     documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_UPPER_CASE})
   */

        if (Ascii.isLowerCase(c)) {
          return true;
        }
      }
      return false;
    }

    private boolean hasUpperCase() {
      for (char c : chars) {
        if (Ascii.isUpperCase(c)) {
          return true;
        }
      }
      return false;
    }

    Alphabet upperCase() {
      if (!hasLowerCase()) {
        return this;
      }