@Test
  public void testGetValidWriteIds() throws Exception {
    GetValidWriteIdsRequest req = new GetValidWriteIdsRequest();
    req.setFullTableNames(Collections.singletonList("foo.bar"));
    txnHandler.getValidWriteIds(req);
  }
Tests to ensure function works even with connection pool size is 1
ql/src/test/org/apache/hadoop/hive/metastore/txn/TestTxnHandlerWithOneConnection.java