assertNull("Empty string should return null", result);
    }

    /**
     * Test decode with null
     *
     * @throws Exception
     */
    public void testDecode_Null() throws Exception {
        final byte[] result = Base64Util.decode(null);
        assertNull("Null should return null", result);
    }

    /**
     * Test encode/decode round trip with various data
     *