JUnit 5 java.lang.ClassNotFoundException: org.junit.platform.engine.support.discovery.SelectorResolv

问题描述：

使用JUnit 5写单元测试时，抛出如下异常：

Connected to the target VM, address: '127.0.0.1:52474', transport: 'socket'
二月 13, 2020 5:50:47 下午 org.junit.platform.launcher.core.DefaultLauncher handleThrowable
警告: TestEngine with ID 'junit-jupiter' failed to discover tests
java.lang.NoClassDefFoundError: org/junit/platform/engine/support/discovery/SelectorResolver
	at org.junit.jupiter.engine.JupiterTestEngine.discover(JupiterTestEngine.java:69)
	at org.junit.platform.launcher.core.DefaultLauncher.discoverEngineRoot(DefaultLauncher.java:177)
	at org.junit.platform.launcher.core.DefaultLauncher.discoverRoot(DefaultLauncher.java:164)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:69)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.ClassNotFoundException: org.junit.platform.engine.support.discovery.SelectorResolver
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 8 more

解决方案

增加junit-platform-launcher依赖即可，如下：

<dependency>
        <groupId>org.junit.platform</groupId>
        <artifactId>junit-platform-launcher</artifactId>
        <version>1.4.0</version>
        <scope>test</scope>
    </dependency>