[ZOOKEEPER-3219] Fix flaky FileChangeWatcherTest

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.6.0, 3.5.5
• Fix Version/s: 3.6.0
• Assignee: Ilya Maykov
• Reporter: Ilya Maykov
• Created: 17/Dec/18 23:22
• Updated: 20/Dec/18 16:52
• Resolved: 20/Dec/18 14:09

Description

A test I committed recently is flaky. Here is an example of failed test output from jenkins:

 

2018-12-17 21:52:53,824 [myid:] - INFO [main:JUnit4ZKTestRunner$LoggedInvokeMethod@77] - RUNNING TEST METHOD testCallbackErrorDoesNotCrashWatcherThread 2018-12-17 21:52:53,826 [myid:] - INFO [FileChangeWatcher:FileChangeWatcher$WatcherThread@193] - FileChangeWatcher thread started 2018-12-17 21:52:54,830 [myid:] - INFO [main:FileChangeWatcherTest@237] - Modifying file 2018-12-17 21:52:54,834 [myid:] - INFO [FileChangeWatcher:FileChangeWatcherTest@222] - Got an update: ENTRY_CREATE zk_test_5141143184635472109 2018-12-17 21:52:54,835 [myid:] - ERROR [FileChangeWatcher:FileChangeWatcher$WatcherThread@238] - Error from callback java.lang.RuntimeException: This error should not crash the watcher thread at org.apache.zookeeper.common.FileChangeWatcherTest.lambda$testCallbackErrorDoesNotCrashWatcherThread$4(FileChangeWatcherTest.java:226) at org.apache.zookeeper.common.FileChangeWatcher$WatcherThread.runLoop(FileChangeWatcher.java:236) at org.apache.zookeeper.common.FileChangeWatcher$WatcherThread.run(FileChangeWatcher.java:205) 2018-12-17 21:52:54,837 [myid:] - INFO [main:FileChangeWatcherTest@244] - Modifying file again 2018-12-17 21:52:54,837 [myid:] - INFO [FileChangeWatcher:FileChangeWatcherTest@222] - Got an update: ENTRY_MODIFY zk_test_5141143184635472109 2018-12-17 21:52:54,838 [myid:] - INFO [FileChangeWatcher:FileChangeWatcherTest@222] - Got an update: ENTRY_MODIFY zk_test_5141143184635472109 2018-12-17 21:52:54,839 [myid:] - INFO [FileChangeWatcher:FileChangeWatcher$WatcherThread@215] - FileChangeWatcher thread finished 2018-12-17 21:52:54,839 [myid:] - INFO [main:JUnit4ZKTestRunner$LoggedInvokeMethod@98] - TEST METHOD FAILED testCallbackErrorDoesNotCrashWatcherThread java.lang.AssertionError: expected:<2> but was:<3> at org.junit.Assert.fail(Assert.java:88) at org.junit.Assert.failNotEquals(Assert.java:834) at org.junit.Assert.assertEquals(Assert.java:645) at org.junit.Assert.assertEquals(Assert.java:631) at org.apache.zookeeper.common.FileChangeWatcherTest.testCallbackErrorDoesNotCrashWatcherThread(FileChangeWatcherTest.java:250) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.apache.zookeeper.JUnit4ZKTestRunner$LoggedInvokeMethod.evaluate(JUnit4ZKTestRunner.java:79) at org.junit.rules.TestWatchman$1.evaluate(TestWatchman.java:53) 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.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at junit.framework.JUnit4TestAdapter.run(JUnit4TestAdapter.java:38) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:535) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:1182) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:1033) 2018-12-17 21:52:54,847 [myid:] - INFO [main:ZKTestCase$1@74] - FAILED testCallbackErrorDoesNotCrashWatcherThread java.lang.AssertionError: expected:<2> but was:<3> at org.junit.Assert.fail(Assert.java:88) at org.junit.Assert.failNotEquals(Assert.java:834) at org.junit.Assert.assertEquals(Assert.java:645) at org.junit.Assert.assertEquals(Assert.java:631) at org.apache.zookeeper.common.FileChangeWatcherTest.testCallbackErrorDoesNotCrashWatcherThread(FileChangeWatcherTest.java:250) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.apache.zookeeper.JUnit4ZKTestRunner$LoggedInvokeMethod.evaluate(JUnit4ZKTestRunner.java:79) at org.junit.rules.TestWatchman$1.evaluate(TestWatchman.java:53) 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.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at junit.framework.JUnit4TestAdapter.run(JUnit4TestAdapter.java:38) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:535) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:1182) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:1033) 2018-12-17 21:52:54,848 [myid:] - INFO [main:ZKTestCase$1@64] - FINISHED testCallbackErrorDoesNotCrashWatcherThread