[HDFS-16932] Mockito causing ClassCastException

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.4.0
• Component/s: hdfs

Environment

Running in the Hadoop development environment in docker, running mvn.

• Assignee: Unassigned
• Reporter: Steve Vaughan
• Created: 23/Feb/23 03:00
• Updated: 23/Feb/23 03:04

Description

Running tests in TestBalancerRPCDelay fails because of ClassCastExceptions introduced by Mockito.  As an example, in this stack trace note that the RedundancyMonitor is calling "isRunning" but incorrectly ends up being routed to getBlocks (which returns BlocksWithLocations) via TestBalancer and a Mockito Spy.  This ultimately is reported as a failure during the shutdown process.

Exception in thread "RedundancyMonitor" java.lang.ClassCastException: java.lang.Boolean cannot be cast to org.apache.hadoop.hdfs.server.protocol.BlocksWithLocations        at org.apache.hadoop.hdfs.server.balancer.TestBalancer$2.answer(TestBalancer.java:1865)        at org.apache.hadoop.hdfs.server.balancer.TestBalancer$2.answer(TestBalancer.java:1858)        at org.mockito.internal.stubbing.StubbedInvocationMatcher.answer(StubbedInvocationMatcher.java:39)        at org.mockito.internal.handler.MockHandlerImpl.handle(MockHandlerImpl.java:96)        at org.mockito.internal.handler.NullResultGuardian.handle(NullResultGuardian.java:29)        at org.mockito.internal.handler.InvocationNotifierHandler.handle(InvocationNotifierHandler.java:35)        at org.mockito.internal.creation.bytebuddy.MockMethodInterceptor.doIntercept(MockMethodInterceptor.java:61)        at org.mockito.internal.creation.bytebuddy.MockMethodInterceptor.doIntercept(MockMethodInterceptor.java:49)        at org.mockito.internal.creation.bytebuddy.MockMethodInterceptor$DispatcherDefaultingToRealMethod.interceptSuperCallable(MockMethodInterceptor.java:108)        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem$MockitoMock$1070381809.isRunning(Unknown Source)        at org.apache.hadoop.hdfs.server.blockmanagement.BlockManager$RedundancyMonitor.run(BlockManager.java:5155)        at java.lang.Thread.run(Thread.java:750)