Currently, integration unit tests using TajoTestingCluster all are included in tajo-core because tajo-core has TajoTestingCluter and QueryTestBase. But, it is hard for other maven modules to have their own unit tests to run queries in a local Tajo cluster. For example, unit tests for client jdbc, and hbase are included in tajo-core. It also makes tajo-core dependencies complicated.
So, we need to separate the unit test kit, such as TajoTestingCluster, QueryTestBase, and ExprTestBase into a separate module.