GenericContainer run from Jupiter tests shouldn't require JUnit 4.x library on runtime classpath

I tried out the JUnit 5 support using the following build script. I’d expect that TestContainers doesn’t require the JUnit 4.x library. As you can see in the build script below, the legacy dependency has been excluded.

apply plugin: 'java-library'

sourceCompatibility = JavaVersion.VERSION_1_8
targetCompatibility = JavaVersion.VERSION_1_8
version = '1.0'

repositories {
    jcenter()
}

dependencies {
    def junitJupiterVersion = '5.3.1'
    testImplementation "org.junit.jupiter:junit-jupiter-api:$junitJupiterVersion"
    testImplementation "org.junit.jupiter:junit-jupiter-params:$junitJupiterVersion"
    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitJupiterVersion"
    testImplementation 'org.testcontainers:junit-jupiter:1.10.1'
}

// IMHO shouldn't be required
configurations.all {
   exclude group: 'junit', module: 'junit'
}

tasks.withType(Test) {
    useJUnitPlatform()
}

In my test case, I am creating a GenericContainer.

import org.junit.jupiter.api.Test;
import org.testcontainers.containers.GenericContainer;
import org.testcontainers.junit.jupiter.Container;
import org.testcontainers.junit.jupiter.Testcontainers;

@Testcontainers
public class TestContainerJunit5Test {
    @Container
    private GenericContainer appContainer = new GenericContainer();

    @Test
    void tryItOut() {
        // do something
    }
}

At runtime I get the following exception. My guess is that GenericContainer still uses JUnit 4.x classes.

java.lang.NoClassDefFoundError: org/junit/rules/TestRule
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.getDeclaredFields0(Native Method)
	at java.lang.Class.privateGetDeclaredFields(Class.java:2583)
	at java.lang.Class.getDeclaredFields(Class.java:1916)
	at org.junit.platform.commons.util.ReflectionUtils.getDeclaredFields(ReflectionUtils.java:1106)
	at org.junit.platform.commons.util.ReflectionUtils.findAllFieldsInHierarchy(ReflectionUtils.java:886)
	at org.junit.platform.commons.util.ReflectionUtils.findFields(ReflectionUtils.java:874)
	at org.junit.platform.commons.util.AnnotationUtils.findAnnotatedFields(AnnotationUtils.java:320)
	at org.junit.platform.commons.util.AnnotationUtils.findAnnotatedFields(AnnotationUtils.java:297)
	at org.junit.jupiter.engine.descriptor.ExtensionUtils.registerExtensionsFromFields(ExtensionUtils.java:92)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.prepare(ClassTestDescriptor.java:154)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.prepare(ClassTestDescriptor.java:74)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$prepare$0(NodeTestTask.java:80)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.prepare(NodeTestTask.java:80)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:66)
	at java.util.ArrayList.forEach(ArrayList.java:1257)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:110)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:95)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:71)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:170)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:154)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:90)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.processAllTestClasses(JUnitPlatformTestClassProcessor.java:92)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor$CollectAllTestClassesExecutor.access$100(JUnitPlatformTestClassProcessor.java:77)
	at org.gradle.api.internal.tasks.testing.junitplatform.JUnitPlatformTestClassProcessor.stop(JUnitPlatformTestClassProcessor.java:73)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.stop(SuiteTestClassProcessor.java:61)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
	at com.sun.proxy.$Proxy2.stop(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.stop(TestWorker.java:131)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:155)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:137)
	at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:404)
	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
	at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: org.junit.rules.TestRule
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 80 more

[detouched]

Here’s a workaround if no dependency on JUnit 4 is a must: create fake TestRule and Statement classes under your test root. Since GenericContainer doesn’t really use them unless run by JUnit 4, this hack works fine.

package org.junit.rules;

@SuppressWarnings("unused")
public interface TestRule {
}

and

package org.junit.runners.model;

@SuppressWarnings("unused")
public class Statement {
}

[gosiapolitowska]

wow, that was a quick response 😃 we switched to Junit5 and are explicitly excluding Junit4 from all dependencies to make sure people don’t use it accidentally or out of habit