由于NoClassDefFoundError:TestEngine，Junit 5测试无法在Eclipse中启动 [英] Junit 5 tests don't launch in Eclipse due to NoClassDefFoundError: TestEngine

问题描述

(对于stackoverflow中的这个问题没有疑问，因此我决定在此处 share 问题与解决方案.)

我想将Spring Boot项目从JUnit 4迁移到JUnit 5，所以我添加了新的API作为依赖项，并删除了旧的API:

   <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
    </dependency>

我想对项目进行完全迁移，因此我明确排除了JUnit 4中的所有内容，并且不包括了junit-vintage-engine(如官方JUnit 5.

仍然没有成功.现在，我收到消息未使用测试运行程序'JUnit 5'找到任何测试.这很令人困惑，因为我在测试方法上使用了正确的JUnit 5批注.Eclipse甚至确认了这一点，因为启动配置'Test method'搜索列出了测试方法就可以了.

一段时间后，我发现测试执行已在控制台中打印了堆栈跟踪:

java.lang.NoClassDefFoundError: org/junit/platform/engine/TestEngine
    at org.junit.platform.launcher.core.ServiceLoaderTestEngineRegistry.loadTestEngines(ServiceLoaderTestEngineRegistry.java:35)
    at org.junit.platform.launcher.core.LauncherFactory.create(LauncherFactory.java:87)
    at org.junit.platform.launcher.core.LauncherFactory.create(LauncherFactory.java:67)
    at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.<init>(JUnit5TestLoader.java:34)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:456)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:370)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:365)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:309)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:224)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:208)
Caused by: java.lang.ClassNotFoundException: org.junit.platform.engine.TestEngine
    at java.net.URLClassLoader.findClass(URLClassLoader.java:444)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:486)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:378)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:419)
    ... 14 more

这使我指出了问题的根本原因(请参见下面的答案)...

解决方案

问题是我缺少对引擎库的依赖:

    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
    </dependency>

然后，测试就像在Eclipse中一样运行.

迁移博客，例如 https ://dev.to/martinbelev/how-to-enable-junit-5-in-new-spring-boot-project-29a8 确实提到了这种依赖性，但是我主要使用share question & solution here.)

I wanted to migrate my Spring Boot project from JUnit 4 to JUnit 5, so I added the new API as dependency and removed the old the ones:

   <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
    </dependency>

I wanted to do a full migration of my project, so I explicitly excluded everything from JUnit 4, and also did not include the junit-vintage-engine (as recommended in the official migration guide).

Then, I did the various changes to make the tests compile, like replacing @Before with @BeforeEach and organizing imports. All in all, this was pretty straightforward.

But running the tests in Eclipse caused some trouble:

• First I got the message "Cannot find 'junit.framework.TestCase' on project build path. JUnit 3 tests can only be run if JUnit is on the build path." In the launch configuration dialog that popped up automatically, I was able to spot my mistake: I needed to select the 'Test runner' JUnit 5.
• Still no success. Now I got the message "No tests found with test runner 'JUnit 5'. This was confusing, because I had used the correct JUnit 5 annotations on the test methods. Eclipse even confirmed this because the launch configuration 'Test method' search listed the test methods just fine.

After I while, I figured out that the test execution had printed a stack trace in the console:

java.lang.NoClassDefFoundError: org/junit/platform/engine/TestEngine
    at org.junit.platform.launcher.core.ServiceLoaderTestEngineRegistry.loadTestEngines(ServiceLoaderTestEngineRegistry.java:35)
    at org.junit.platform.launcher.core.LauncherFactory.create(LauncherFactory.java:87)
    at org.junit.platform.launcher.core.LauncherFactory.create(LauncherFactory.java:67)
    at org.eclipse.jdt.internal.junit5.runner.JUnit5TestLoader.<init>(JUnit5TestLoader.java:34)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:456)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createRawTestLoader(RemoteTestRunner.java:370)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.createLoader(RemoteTestRunner.java:365)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.defaultInit(RemoteTestRunner.java:309)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.init(RemoteTestRunner.java:224)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:208)
Caused by: java.lang.ClassNotFoundException: org.junit.platform.engine.TestEngine
    at java.net.URLClassLoader.findClass(URLClassLoader.java:444)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:486)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:378)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:419)
    ... 14 more

This pointed me to the root cause of the problem (see answer below)...

解决方案

The problem was that I was missing the dependency to the engine library:

    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-engine</artifactId>
    </dependency>

Then, the tests run like a charm in Eclipse.

Migration blogs like https://dev.to/martinbelev/how-to-enable-junit-5-in-new-spring-boot-project-29a8 do mention this dependency, but I primarily worked with the JUnit 5 documentation, and somehow I must have overlooked this important piece of information there...

这篇关于由于NoClassDefFoundError:TestEngine，Junit 5测试无法在Eclipse中启动的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！