code: public void testDelete_CheckTimestampUpdated() throws IOException {
    byte[] row1=Bytes.toBytes("row1");
    byte[] col1=Bytes.toBytes("col1");
    byte[] col2=Bytes.toBytes("col2");
    byte[] col3=Bytes.toBytes("col3");
    String method=this.getName();
    initHRegion(tableName,method,fam1);
    List<KeyValue> kvs=new ArrayList<KeyValue>();
    kvs.add(new KeyValue(row1,fam1,col1,null));
    kvs.add(new KeyValue(row1,fam1,col2,null));
    kvs.add(new KeyValue(row1,fam1,col3,null));
    Map<byte[],List<KeyValue>> deleteMap=new HashMap<byte[],List<KeyValue>>();
    deleteMap.put(fam1,kvs);
    region.delete(deleteMap,true);
    long now=System.currentTimeMillis();
    KeyValue firstKv=region.getStore(fam1).memstore.kvset.first();
    assertTrue(firstKv.getTimestamp() <= now);
    now=firstKv.getTimestamp();
    for (  KeyValue kv : region.getStore(fam1).memstore.kvset) {
      assertTrue(kv.getTimestamp() <= now);
      now=kv.getTimestamp();
    }
  }
  