[FLINK-9847] OneInputStreamTaskTest.testWatermarksNotForwardedWithinChainWhenIdle unstable

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.6.0
• Fix Version/s: 1.5.2, 1.6.0
• Component/s: Tests
• Labels: test-stability
• Assignee: Unassigned
• Reporter: Till Rohrmann
• Created: 13/Jul/18 14:25
• Updated: 16/Jul/18 12:47
• Resolved: 16/Jul/18 12:47

Description

The test OneInputStreamTaskTest.testWatermarksNotForwardedWithinChainWhenIdle is unstable. When executing repeatedly the test fails from time to time with

java.lang.Exception: error in task

	at org.apache.flink.streaming.runtime.tasks.StreamTaskTestHarness.waitForTaskCompletion(StreamTaskTestHarness.java:250)
	at org.apache.flink.streaming.runtime.tasks.StreamTaskTestHarness.waitForTaskCompletion(StreamTaskTestHarness.java:233)
	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTaskTest.testWatermarksNotForwardedWithinChainWhenIdle(OneInputStreamTaskTest.java:348)
	at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55)
	at org.junit.rules.RunRules.evaluate(RunRules.java:20)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:67)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.mockito.exceptions.misusing.WrongTypeOfReturnValue: 
Boolean cannot be returned by getChannelIndex()
getChannelIndex() should return int
***
If you're unsure why you're getting above error read on.
Due to the nature of the syntax above problem might occur because:
1. This exception *might* occur in wrongly written multi-threaded tests.
   Please refer to Mockito FAQ on limitations of concurrency testing.
2. A spy is stubbed using when(spy.foo()).then() syntax. It is safer to stub spies - 
   - with doReturn|Throw() family of methods. More in javadocs for Mockito.spy() method.

	at org.apache.flink.streaming.runtime.io.BarrierBuffer.getNextNonBlocked(BarrierBuffer.java:165)
	at org.apache.flink.streaming.runtime.io.StreamInputProcessor.processInput(StreamInputProcessor.java:209)
	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:105)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:300)
	at org.apache.flink.streaming.runtime.tasks.StreamTaskTestHarness$TaskThread.run(StreamTaskTestHarness.java:437)

Given the exception I suspect that there is a problem with mocking in the OneInputStreamTaskTestHarness.

Issue Links

• is superceded by: FLINK-8731 TwoInputStreamTaskTest flaky on travis