TestRecovery.testSpeculative fails if testCrashed fails

The test testSpeculative in org.apache.hadoop.mapreduce.v2.app.TestRecovery is unstable.

Based on my findings, the test itself is not problematic. It only fails if testCrashed in the same class fails before it.

The reason is not completely clear to me, but I whenever I explicitly stop the MRAppMaster in testCrashed in a finally block, then the issue disappears. I think the reason is that both tests uses the same folder for staging.

Solution: wrap logic in testCrashed in a try-finally block and then stop the MRAppMaster.