Hey Cheolsoo Park, I think the issue is with the fact that MiniCluster.buildCluster() generates a hadoop-site.xml file under build/classes. However, MiniCluster.shutDown() does not delete this file. Ideally, hadoop-site.xml should be deleted on cluster shutdown.
With respect to TestHExecutionEngine, the issue is with the fact a previous test run that uses mini-cluster generates hadoop-site.xml and does not delete it. At the time TestHExecutionEngine runs this file is present on the classpath but mini-dfs and mini-mr were shutdown at the completion of previous test. pigContext.connect() in TestHExecutionEngine tries to establish a connection with mini-cluster which is no longer up.
The fix would be to:
1. Delete hadoop-site-xml on mini-cluster shutdown (to be done in another JIRA)
2. Check if this patch stabilizes (and nothing else breaks)
Does that make sense?