java.lang.NullPointerException: The mapper [reactor.core.publisher.FluxOnAssemblyTest$$Lambda$453/1253691744] returned a null value. at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:108) Suppressed: The stacktrace has been enhanced by Reactor, refer to additional information below: Assembly trace from producer [reactor.core.publisher.FluxMap] : reactor.core.publisher.Flux.map(Flux.java:6633) reactor.core.publisher.FluxOnAssemblyTest.lambda$checkpointEmptyForParallel$23(FluxOnAssemblyTest.java:535) Error has been observed at the following site(s): *______________________Flux.map ⇢ at reactor.core.publisher.FluxOnAssemblyTest.lambda$checkpointEmptyForParallel$23(FluxOnAssemblyTest.java:535) *__ParallelFlux.transformGroups ⇢ at reactor.core.publisher.FluxOnAssemblyTest.checkpointEmptyForParallel(FluxOnAssemblyTest.java:535) |_ ParallelFlux.transformGroups ⇢ at reactor.core.publisher.FluxOnAssemblyTest.checkpointEmptyForParallel(FluxOnAssemblyTest.java:535) |_ checkpoint() ⇢ at reactor.core.publisher.FluxOnAssemblyTest.checkpointEmptyForParallel(FluxOnAssemblyTest.java:536) |_ ParallelFlux.sequential ⇢ at reactor.core.publisher.FluxOnAssemblyTest.checkpointEmptyForParallel(FluxOnAssemblyTest.java:537) Original Stack Trace: at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:108) at reactor.core.publisher.ParallelGroup$ParallelInnerGroup.onNext(ParallelGroup.java:141) at reactor.core.publisher.ParallelSource$ParallelSourceMain.drainSync(ParallelSource.java:425) at reactor.core.publisher.ParallelSource$ParallelSourceMain.drain(ParallelSource.java:463) at reactor.core.publisher.ParallelSource$ParallelSourceMain$ParallelSourceInner.request(ParallelSource.java:511) at reactor.core.publisher.ParallelGroup$ParallelInnerGroup.onSubscribe(ParallelGroup.java:134) at reactor.core.publisher.ParallelSource$ParallelSourceMain.setupSubscribers(ParallelSource.java:221) at reactor.core.publisher.ParallelSource$ParallelSourceMain.onSubscribe(ParallelSource.java:186) at reactor.core.publisher.FluxRange.subscribe(FluxRange.java:69) at reactor.core.publisher.Flux.subscribe(Flux.java:8891) at reactor.core.publisher.ParallelSource.subscribe(ParallelSource.java:90) at reactor.core.publisher.ParallelGroup.subscribe(ParallelGroup.java:59) at reactor.core.publisher.Flux.subscribe(Flux.java:8891) at reactor.core.publisher.ParallelSource.subscribe(ParallelSource.java:90) at reactor.core.publisher.ParallelMergeSequential.subscribe(ParallelMergeSequential.java:75) at reactor.core.publisher.Flux.subscribe(Flux.java:8891) at reactor.test.DefaultStepVerifierBuilder$DefaultStepVerifier.toVerifierAndSubscribe(DefaultStepVerifierBuilder.java:891) at reactor.test.DefaultStepVerifierBuilder$DefaultStepVerifier.verify(DefaultStepVerifierBuilder.java:831) at reactor.test.DefaultStepVerifierBuilder$DefaultStepVerifier.verify(DefaultStepVerifierBuilder.java:823) at reactor.test.DefaultStepVerifierBuilder.verifyError(DefaultStepVerifierBuilder.java:665) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:767) at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60) at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131) at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156) at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147) at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestTemplateMethod(TimeoutExtension.java:94) at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103) at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93) at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45) at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37) at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92) at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$8(TestMethodTestDescriptor.java:217) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138) at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:156) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35) at org.junit.platform.engine.support.hierarchical.NodeTestTask$DefaultDynamicTestExecutor.execute(NodeTestTask.java:231) at org.junit.platform.engine.support.hierarchical.NodeTestTask$DefaultDynamicTestExecutor.execute(NodeTestTask.java:209) at org.junit.jupiter.engine.descriptor.TestTemplateTestDescriptor.execute(TestTemplateTestDescriptor.java:141) at org.junit.jupiter.engine.descriptor.TestTemplateTestDescriptor.lambda$execute$3(TestTemplateTestDescriptor.java:109) at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183) at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:948) at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150) at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173) at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485) at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:272) at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1384) at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150) at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173) at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485) at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:272) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1384) at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150) at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173) at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485) at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:272) at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1384) at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150) at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173) at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:485) at org.junit.jupiter.engine.descriptor.TestTemplateTestDescriptor.execute(TestTemplateTestDescriptor.java:109) at org.junit.jupiter.engine.descriptor.TestTemplateTestDescriptor.execute(TestTemplateTestDescriptor.java:43) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:156) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100) at java.util.ArrayList.forEach(ArrayList.java:1259) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:160) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100) at java.util.ArrayList.forEach(ArrayList.java:1259) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:160) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:146) at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:144) at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:143) at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:100) at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35) at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57) at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:198) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:169) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:93) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:58) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:141) at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:57) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:103) at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:85) at org.junit.platform.launcher.core.DelegatingLauncher.execute(DelegatingLauncher.java:47) at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:119) at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:94) at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:89) at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:62) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36) at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24) at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33) at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94) at com.sun.proxy.$Proxy2.stop(Unknown Source) at org.gradle.api.internal.tasks.testing.worker.TestWorker$3.run(TestWorker.java:193) at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129) at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100) at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60) at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56) at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:113) at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:65) at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69) at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)