public void testHexDecodeInvalidStrings() {
        try {
            EncodingTool.hexDecode("zz");
            fail("Expecting IllegalArgumentException");
        } catch (IllegalArgumentException ex) {
            if (DEBUG) {
                System.out.println(ex.getMessage());
            }
        }
        try {
            EncodingTool.hexDecode("bad"); // Uneven length
            fail("Expecting IllegalArgumentException");
        } catch (IllegalArgumentException ex) {
            if (DEBUG) {
                System.out.println(ex.getMessage());
            }
        }
    }