org.mockito.exceptions.misusing.UnfinishedStubbingException: 
Unfinished stubbing detected here:
-> at org.apache.pulsar.functions.worker.FunctionAssignmentTailerTest.testErrorNotifier(FunctionAssignmentTailerTest.java:164)

E.g. thenReturn() may be missing.
Examples of correct stubbing:
    when(mock.isOk()).thenReturn(true);
    when(mock.isOk()).thenThrow(exception);
    doThrow(exception).when(mock).someVoidMethod();
Hints:
 1. missing thenReturn()
 2. you are trying to stub a final method, which is not supported
 3. you are stubbing the behaviour of another mock inside before 'thenReturn' instruction is completed, possibly on another thread


	at org.apache.pulsar.functions.worker.FunctionRuntimeManager.processAssignmentMessage(FunctionRuntimeManager.java:683)
	at org.apache.pulsar.functions.worker.FunctionAssignmentTailerTest.testErrorNotifier(FunctionAssignmentTailerTest.java:164)
	at jdk.internal.reflect.GeneratedMethodAccessor27.invoke(Unknown Source)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.testng.internal.invokers.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:139)
	at org.testng.internal.invokers.InvokeMethodRunnable.runOne(InvokeMethodRunnable.java:47)
	at org.testng.internal.invokers.InvokeMethodRunnable.call(InvokeMethodRunnable.java:76)
	at org.testng.internal.invokers.InvokeMethodRunnable.call(InvokeMethodRunnable.java:11)
	at java.base/java.util.concurrent.FutureTask.run$$$capture(FutureTask.java:264)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java)
	at --- Async.Stack.Trace --- (captured by IntelliJ IDEA debugger)
	at java.base/java.util.concurrent.FutureTask.<init>(FutureTask.java:132)
	at java.base/java.util.concurrent.AbstractExecutorService.newTaskFor(AbstractExecutorService.java:113)
	at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:144)
	at org.testng.internal.invokers.MethodInvocationHelper.invokeWithTimeoutWithNewExecutor(MethodInvocationHelper.java:385)
	at org.testng.internal.invokers.MethodInvocationHelper.invokeWithTimeout(MethodInvocationHelper.java:303)
	at org.testng.internal.invokers.TestInvoker.invokeMethod(TestInvoker.java:686)
	at org.testng.internal.invokers.TestInvoker.invokeTestMethod(TestInvoker.java:221)
	at org.testng.internal.invokers.MethodRunner.runInSequence(MethodRunner.java:50)
	at org.testng.internal.invokers.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:969)
	at org.testng.internal.invokers.TestInvoker.invokeTestMethods(TestInvoker.java:194)
	at org.testng.internal.invokers.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:148)
	at org.testng.internal.invokers.TestMethodWorker.run(TestMethodWorker.java:128)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at org.testng.TestRunner.privateRun(TestRunner.java:829)
	at org.testng.TestRunner.run(TestRunner.java:602)
	at org.testng.SuiteRunner.runTest(SuiteRunner.java:437)
	at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:431)
	at org.testng.SuiteRunner.privateRun(SuiteRunner.java:391)
	at org.testng.SuiteRunner.run(SuiteRunner.java:330)
	at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
	at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:95)
	at org.testng.TestNG.runSuitesSequentially(TestNG.java:1256)
	at org.testng.TestNG.runSuitesLocally(TestNG.java:1176)
	at org.testng.TestNG.runSuites(TestNG.java:1099)
	at org.testng.TestNG.run(TestNG.java:1067)
	at com.intellij.rt.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:65)
	at com.intellij.rt.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:105)