### Question:
ChecksumHelper { protected byte[] addChecksum(byte[] source) { CRC32 crc32 = new CRC32(); crc32.update(source); long checkSum = crc32.getValue(); byte[] checkSumBytes = String.valueOf(checkSum).getBytes(); byte[] concat = Bytes.concat(source, (SEPARATOR+"").getBytes(), checkSumBytes); return concat; }    }### Answer:
@Test public void testAddChecksum() { ChecksumHelper checksumHelper = new ChecksumHelper(); byte[] source = "foobarbaz".getBytes(); log.debug("source : " + new String(source)); byte[] withChecksum = checksumHelper.addChecksum(source); log.debug("withChecksum: " + new String(withChecksum)); assertEquals("foobarbaz#444082090", new String(withChecksum)); }