private long openTxn() throws MetaException {
    List<Long> txns = txnHandler.openTxns(new OpenTxnRequest(1, "me", "localhost")).getTxn_ids();
    return txns.get(0);
  }
This test checks that the transaction handler works when the connection pool is set to none.
ql/src/test/org/apache/hadoop/hive/metastore/txn/TestTxnHandlerNoConnectionPool.java