`MicrometerObservationRegistryTestExecutionListener` uses wrong `ClassLoader` to detect dependencies

[lynchie14]

This occurred have updating from 3.0.7->3.0.8

Reproduced on clean app

Create a simple demo app with 3.0.8 using https://start.spring.io/

Add

implementation 'org.springframework.boot:spring-boot-starter-web'

testImplementation 'org.springframework.boot:spring-boot-starter-test'

testImplementation 'org.codehaus.groovy:groovy-all:3.0.17'

Now, run the DemoApplicationTests in the generated demo project.

It will fail with java.lang.NoClassDefFoundError: io/micrometer/context/ThreadLocalAccessor

> Task :compileJava UP-TO-DATE
> Task :processResources UP-TO-DATE
> Task :classes UP-TO-DATE
> Task :compileTestJava UP-TO-DATE
> Task :processTestResources NO-SOURCE
> Task :testClasses UP-TO-DATE
> Task :test
13:56:44.043 [Test worker] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Neither @ContextConfiguration nor @ContextHierarchy found for test class [DemoApplicationTests]: using SpringBootContextLoader
13:56:44.047 [Test worker] DEBUG org.springframework.test.context.support.AbstractContextLoader -- Could not detect default resource locations for test class [com.example.demo.DemoApplicationTests]: no resource found for suffixes {-context.xml, Context.groovy}.
13:56:44.047 [Test worker] INFO org.springframework.test.context.support.AnnotationConfigContextLoaderUtils -- Could not detect default configuration classes for test class [com.example.demo.DemoApplicationTests]: DemoApplicationTests does not declare any static, non-private, non-final, nested classes annotated with @Configuration.
13:56:44.065 [Test worker] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Using ContextCustomizers for test class [DemoApplicationTests]: [DisableObservabilityContextCustomizer, PropertyMappingContextCustomizer, Customizer, ExcludeFilterContextCustomizer, DuplicateJsonObjectContextCustomizer, MockitoContextCustomizer, TestRestTemplateContextCustomizer]
13:56:44.112 [Test worker] DEBUG org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider -- Identified candidate component class: file [C:\temp\sb3.0.8\demo\build\classes\java\main\com\example\demo\DemoApplication.class]
13:56:44.113 [Test worker] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Found @SpringBootConfiguration com.example.demo.DemoApplication for test class com.example.demo.DemoApplicationTests
13:56:44.205 [Test worker] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Could not load TestExecutionListener [org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener]. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes available.
java.lang.ExceptionInInitializerError: null
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
	at org.springframework.core.io.support.SpringFactoriesLoader$FactoryInstantiator.instantiate(SpringFactoriesLoader.java:382)
	at org.springframework.core.io.support.SpringFactoriesLoader.instantiateFactory(SpringFactoriesLoader.java:228)
	at org.springframework.core.io.support.SpringFactoriesLoader.load(SpringFactoriesLoader.java:206)
	at org.springframework.core.io.support.SpringFactoriesLoader.load(SpringFactoriesLoader.java:178)
	at org.springframework.test.context.util.TestContextSpringFactoriesUtils.loadFactoryImplementations(TestContextSpringFactoriesUtils.java:71)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.getDefaultTestExecutionListeners(AbstractTestContextBootstrapper.java:198)
	at org.springframework.boot.test.context.SpringBootTestContextBootstrapper.getDefaultTestExecutionListeners(SpringBootTestContextBootstrapper.java:128)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.getTestExecutionListeners(AbstractTestContextBootstrapper.java:128)
	at org.springframework.test.context.TestContextManager.<init>(TestContextManager.java:131)
	at org.springframework.test.context.TestContextManager.<init>(TestContextManager.java:113)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.lambda$getOrComputeIfAbsent$4(ExtensionValuesStore.java:86)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$MemoizingSupplier.computeValue(ExtensionValuesStore.java:223)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$MemoizingSupplier.get(ExtensionValuesStore.java:211)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$StoredValue.evaluate(ExtensionValuesStore.java:191)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$StoredValue.access$100(ExtensionValuesStore.java:171)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.getOrComputeIfAbsent(ExtensionValuesStore.java:89)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.getOrComputeIfAbsent(ExtensionValuesStore.java:93)
	at org.junit.jupiter.engine.execution.NamespaceAwareStore.getOrComputeIfAbsent(NamespaceAwareStore.java:61)
	at org.springframework.test.context.junit.jupiter.SpringExtension.getTestContextManager(SpringExtension.java:294)
	at org.springframework.test.context.junit.jupiter.SpringExtension.beforeAll(SpringExtension.java:113)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeBeforeAllCallbacks$12(ClassBasedTestDescriptor.java:395)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeBeforeAllCallbacks(ClassBasedTestDescriptor.java:395)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:211)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:84)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:148)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:147)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:127)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:90)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:55)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:102)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:54)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:99)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:79)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:75)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:62)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
	at jdk.proxy1/jdk.proxy1.$Proxy2.stop(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker$3.run(TestWorker.java:193)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)
	at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
	at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:113)
	at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:65)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
Caused by: java.lang.IllegalStateException: MicrometerObservationRegistryTestExecutionListener requires micrometer-observation 1.10.8 or higher
	at org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.<clinit>(MicrometerObservationRegistryTestExecutionListener.java:80)
	... 83 common frames omitted
Caused by: java.lang.NoClassDefFoundError: io/micrometer/context/ThreadLocalAccessor
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1012)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150)
	at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:862)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:760)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:681)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:639)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
	at java.base/java.lang.Class.forName0(Native Method)
	at java.base/java.lang.Class.forName(Class.java:467)
	at org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.<clinit>(MicrometerObservationRegistryTestExecutionListener.java:76)
	... 83 common frames omitted
Caused by: java.lang.ClassNotFoundException: io.micrometer.context.ThreadLocalAccessor
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
	... 95 common frames omitted
13:56:44.212 [Test worker] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Skipping candidate TestExecutionListener [org.springframework.test.context.transaction.TransactionalTestExecutionListener] due to a missing dependency. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes and their required dependencies available. Offending class: [org/springframework/transaction/interceptor/TransactionAttributeSource]
13:56:44.214 [Test worker] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Skipping candidate TestExecutionListener [org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener] due to a missing dependency. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes and their required dependencies available. Offending class: [org/springframework/transaction/interceptor/TransactionAttribute]
13:56:44.216 [Test worker] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper -- Using TestExecutionListeners for test class [DemoApplicationTests]: [ServletTestExecutionListener, DirtiesContextBeforeModesTestExecutionListener, ApplicationEventsTestExecutionListener, MockitoTestExecutionListener, DependencyInjectionTestExecutionListener, DirtiesContextTestExecutionListener, EventPublishingTestExecutionListener, RestDocsTestExecutionListener, MockRestServiceServerResetTestExecutionListener, MockMvcPrintOnlyOnFailureTestExecutionListener, WebDriverTestExecutionListener, MockWebServiceServerTestExecutionListener, ResetMocksTestExecutionListener]
13:56:44.217 [Test worker] DEBUG org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener -- Before test class: class [DemoApplicationTests], class annotated with @DirtiesContext [false] with mode [null]

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v3.0.8)

2023-06-22T13:56:44.465+01:00  INFO 24116 --- [    Test worker] com.example.demo.DemoApplicationTests    : Starting DemoApplicationTests using Java 17.0.6 with PID 24116 (started by SLynch in C:\temp\sb3.0.8\demo)
2023-06-22T13:56:44.466+01:00  INFO 24116 --- [    Test worker] com.example.demo.DemoApplicationTests    : No active profile set, falling back to 1 default profile: "default"
2023-06-22T13:56:45.535+01:00  WARN 24116 --- [    Test worker] .b.a.g.t.GroovyTemplateAutoConfiguration : Cannot find template location: classpath:/templates/ (please add some templates, check your Groovy configuration, or set spring.groovy.template.check-template-location=false)
2023-06-22T13:56:45.926+01:00  INFO 24116 --- [    Test worker] com.example.demo.DemoApplicationTests    : Started DemoApplicationTests in 1.654 seconds (process running for 2.587)
BUILD SUCCESSFUL in 3s
4 actionable tasks: 1 executed, 3 up-to-date
13:56:46: Execution finished ':test --tests "com.example.demo.DemoApplicationTests"'.

From looking at the dependencies, the missing classes are part of micrometer-propagation which is only an optional dependency of
micrometer-observation-1.10.8.pom

<dependency>
<groupId>io.micrometer</groupId>
<artifactId>context-propagation</artifactId>
<version>1.0.3</version>
<scope>compile</scope>
<optional>true</optional>
</dependency>

Should the spring-web pom have a compile dependency on the above package too?

[snicoll]

I can't reproduce the issue that you've described. How do you run the test? Have you tried on the command line?

[lynchie14]

I can also see it using ./gradlew test --debug.

I was running this in Intellij simply by running the test.

The output is DEBUG only and on reflection it doesn't prevent the tests from running however this stacktrace never appeared in 3.0.7.

However, I'm not sure if this causes issues at runtime if Micrometer is enabled.

[snicoll]

That's how the TestContext framework works I am afraid. It'll load the execution listener and prints such a stacktrace if the class can't be loaded (due to a missing optional dependency).

Moving to framework for their consideration as this class is not part of Spring Boot.

[wilkinsona]

The class should be there with Micrometer 10.1.8. I can only reproduce this specific failure by downgrading Micrometer to 1.10.7.

With 1.10.8 I see a different exception being logged at debug level:

14:26:26.781 [Test worker] DEBUG org.springframework.test.context.util.TestContextSpringFactoriesUtils -- Could not load TestExecutionListener [org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener]. Specify custom TestExecutionListener classes or make the default TestExecutionListener classes available.
java.lang.ExceptionInInitializerError: null
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
	at org.springframework.core.io.support.SpringFactoriesLoader$FactoryInstantiator.instantiate(SpringFactoriesLoader.java:382)
	at org.springframework.core.io.support.SpringFactoriesLoader.instantiateFactory(SpringFactoriesLoader.java:228)
	at org.springframework.core.io.support.SpringFactoriesLoader.load(SpringFactoriesLoader.java:206)
	at org.springframework.core.io.support.SpringFactoriesLoader.load(SpringFactoriesLoader.java:178)
	at org.springframework.test.context.util.TestContextSpringFactoriesUtils.loadFactoryImplementations(TestContextSpringFactoriesUtils.java:71)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.getDefaultTestExecutionListeners(AbstractTestContextBootstrapper.java:198)
	at org.springframework.boot.test.context.SpringBootTestContextBootstrapper.getDefaultTestExecutionListeners(SpringBootTestContextBootstrapper.java:128)
	at org.springframework.test.context.support.AbstractTestContextBootstrapper.getTestExecutionListeners(AbstractTestContextBootstrapper.java:128)
	at org.springframework.test.context.TestContextManager.<init>(TestContextManager.java:131)
	at org.springframework.test.context.TestContextManager.<init>(TestContextManager.java:113)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.lambda$getOrComputeIfAbsent$4(ExtensionValuesStore.java:86)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$MemoizingSupplier.computeValue(ExtensionValuesStore.java:223)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$MemoizingSupplier.get(ExtensionValuesStore.java:211)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$StoredValue.evaluate(ExtensionValuesStore.java:191)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore$StoredValue.access$100(ExtensionValuesStore.java:171)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.getOrComputeIfAbsent(ExtensionValuesStore.java:89)
	at org.junit.jupiter.engine.execution.ExtensionValuesStore.getOrComputeIfAbsent(ExtensionValuesStore.java:93)
	at org.junit.jupiter.engine.execution.NamespaceAwareStore.getOrComputeIfAbsent(NamespaceAwareStore.java:61)
	at org.springframework.test.context.junit.jupiter.SpringExtension.getTestContextManager(SpringExtension.java:294)
	at org.springframework.test.context.junit.jupiter.SpringExtension.beforeAll(SpringExtension.java:113)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.lambda$invokeBeforeAllCallbacks$12(ClassBasedTestDescriptor.java:395)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.invokeBeforeAllCallbacks(ClassBasedTestDescriptor.java:395)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:211)
	at org.junit.jupiter.engine.descriptor.ClassBasedTestDescriptor.before(ClassBasedTestDescriptor.java:84)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:148)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141)
	at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:107)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:88)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:54)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:67)
	at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:52)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86)
	at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86)
	at org.junit.platform.launcher.core.SessionPerRequestLauncher.execute(SessionPerRequestLauncher.java:53)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:99)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$000(JUnitPlatformTestClassProcessor.java:79)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:75)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:62)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
	at jdk.proxy1/jdk.proxy1.$Proxy2.stop(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker$3.run(TestWorker.java:193)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)
	at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
	at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:113)
	at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:65)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
	at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)
Caused by: java.lang.IllegalStateException: MicrometerObservationRegistryTestExecutionListener requires micrometer-observation 1.10.8 or higher
	at org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.<clinit>(MicrometerObservationRegistryTestExecutionListener.java:80)
	... 82 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/junit/platform/launcher/TestExecutionListener
	at org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.<clinit>(MicrometerObservationRegistryTestExecutionListener.java:76)
	... 82 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.junit.platform.launcher.TestExecutionListener
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
	... 83 common frames omitted

I believe it's happening because it's referring to org.junit.platform.launcher.TestExecutionListener:

			clazz = Class.forName(OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME, true,
					TestExecutionListener.class.getClassLoader());

I think it should have been org.springframework.test.context.TestExecutionListener.

[wilkinsona]

Trying to work around the reference to the wrong TestExecutionListener, I added this dependency:

testRuntimeOnly 'org.junit.platform:junit-platform-launcher'

I now see the failure that was originally reported. Perhaps because the wrong ClassLoader is being used to load io.micrometer.context.ThreadLocalAccessor?

[sbrannen]

I believe it's happening because it's referring to org.junit.platform.launcher.TestExecutionListener:

Good catch, @wilkinsona!

And... that's embarrassing.

I'll fix that right away.