The test 'org.apache.hadoop.mapreduce.jobhistory.TestJobHistoryEventHandler.testSigTermedFunctionality' is not idempotent and fails if run twice in the same JVM, because it pollutes state shared among tests. It may be good to clean this state pollution so that some other tests do not fail in the future due to the shared state polluted by this test.
Running `TestJobHistoryEventHandler.testSigTermedFunctionality` twice would result in the second run failing due to `NullPointerException`shown in the following:
The root cause of this is that running 'TestJobHistoryEventHandler.testSigTermedFunctionality' results in some entries to be added to the static 'JobHistoryEventHandler.fileMap'. The entries in the 'fileMap' are not cleaned up when the test is done, resulting in a NullPointerException in the second run as the stale object(added in the first run) in the 'fileMap' is accessed.