### Question:
CSN implements Serializable, Comparable<CSN> { @Override public String toString() { final StringBuilder buffer = new StringBuilder(); toString(buffer); return buffer.toString(); } CSN(String str);  CSN(long timeStamp, int seqNum, int serverId); static CSN valueOf(String s); static CSN valueOf(ByteSequence bs); long getTime(); long getTimeSec(); int getSeqnum(); int getServerId(); @Override boolean equals(Object obj); @Override int hashCode(); ByteString toByteString(); void toByteString(ByteStringBuilder builder); @Override String toString(); String toStringUI(); static int compare(CSN csn1, CSN csn2); static int diffSeqNum(CSN csn1, CSN csn2); boolean isOlderThan(CSN csn); boolean isOlderThanOrEqualTo(CSN csn); boolean isNewerThanOrEqualTo(CSN csn); boolean isNewerThan(CSN csn); @Override int compareTo(CSN csn); static final int BYTE_ENCODING_LENGTH; static final int STRING_ENCODING_LENGTH; static final CSN MAX_CSN_VALUE; }### Answer:
@Test(dataProvider = "csnData") public void createCSN(long time, int seq, int id, String str) throws Exception { CSN csn = new CSN(time, seq, id); assertEquals(csn.toString(), str); new CSN(time, seq, id); new CSN(time+1, seq, id); new CSN(time, seq+1, id); new CSN(time, seq, id+1); }
@Test(dataProvider = "csnData") public void csnEncodeDecode(long time, int seq, int id, String str) throws Exception { CSN csn = new CSN(time, seq, id); CSN csn2 = new CSN(csn.toString()); assertEquals(csn, csn2, "The encoding/decoding is not reversible"); assertEquals(csn2.toString(), str, "The encoding/decoding of CSN is not reversible for toString()"); }