Hi folks, I've added a brief unit test class for PreLogicalPlanVerifier. Currently, we are lazy to add unit tests for semantic and logical plan verifier. With this, we can easily add unit tests. Please use this for verifier codes.
https://github.com/apache/tajo/pull/164/files#diff-a5fa52223cbe8fcf8d443eafe5ed88dfR71 Thanks, Hyunsik
