@Test
public void testTransaction() throws Exception {

  when(this.queryRunner.update(this.conn, "update blah set ? = ?", "1", 26)).thenReturn(1);
  when(this.queryRunner.query(this.conn, "select * from blah where ? = ?", this.handler, "id", 1))
      .thenReturn(26);
  final SQLTransaction<Integer> transaction = transOperator -> {
    transOperator.update("update blah set ? = ?", "1", 26);
    return transOperator.query("select * from blah where ? = ?", this.handler, "id", 1);
  };
  final int res = this.dbOperator.transaction(transaction);
  Assert.assertEquals(26, res);
}