Maven+Kotlin项目JUnit5测试报错：TestEngine 'junit-jupiter'无法发现测试

错误详情 #

运行JUnit5测试时触发以下错误：

TestEngine with ID 'junit-jupiter' failed to discover tests

完整错误堆栈：

org.junit.platform.commons.JUnitException: TestEngine with ID 'junit-jupiter' failed to discover tests
    at org.junit.platform.launcher.core.DefaultLauncher.discoverEngineRoot(DefaultLauncher.java:189)
    at org.junit.platform.launcher.core.DefaultLauncher.discoverRoot(DefaultLauncher.java:168)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:132)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:57)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:232)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:55)
Caused by: java.lang.NoClassDefFoundError: org/junit/jupiter/api/ClassOrderer
    at org.junit.jupiter.engine.config.DefaultJupiterConfiguration.<clinit>(DefaultJupiterConfiguration.java:50)
    at org.junit.jupiter.engine.JupiterTestEngine.discover(JupiterTestEngine.java:66)
    at org.junit.platform.launcher.core.DefaultLauncher.discoverEngineRoot(DefaultLauncher.java:181)
    ... 8 more
Caused by: java.lang.ClassNotFoundException: org.junit.jupiter.api.ClassOrderer
    at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
    ... 11 more

环境信息 #

• JUnit Jupiter Engine版本：5.8.2（已尝试5.9.0等版本）
• Maven Surefire Plugin版本：2.22.2
• IDE：IntelliJ Community Edition 2023.1.3
• 项目类型：Maven+Kotlin

问题根源 #

从堆栈信息看，核心问题是ClassNotFoundException: org.junit.jupiter.api.ClassOrderer，该类属于JUnit Jupiter API模块，引发原因包括：

1. Kotlin测试依赖与JUnit版本不兼容
2. pom.xml中存在重复依赖，导致Maven依赖解析异常
3. Surefire插件版本过旧，无法适配新版本JUnit5

解决方案 #

1. 清理重复依赖 #

移除pom.xml中重复的kotlin-stdlib-jdk8依赖，仅保留使用${kotlin.version}变量的版本。

2. 统一依赖版本 #

确保kotlin-test-junit5版本与项目kotlin.version一致，避免版本冲突；同时统一JUnit5版本，使用聚合依赖简化配置。

3. 更新Surefire插件版本 #

将maven-surefire-plugin和maven-failsafe-plugin升级到3.0.0及以上版本，更好支持JUnit5。

修正后的pom.xml #

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://maven.apache.org/POM/4.0.0"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <artifactId>Airline</artifactId>
    <groupId>org.example</groupId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>consoleApp</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <kotlin.code.style>official</kotlin.code.style>
        <kotlin.compiler.jvmTarget>1.8</kotlin.compiler.jvmTarget>
        <kotlin.version>1.9.0</kotlin.version>
        <junit-jupiter.version>5.9.2</junit-jupiter.version>
        <maven-surefire.version>3.1.2</maven-surefire.version>
    </properties>

    <repositories>
        <repository>
            <id>mavenCentral</id>
            <url>https://repo1.maven.org/maven2/</url>
        </repository>
    </repositories>

    <build>
        <sourceDirectory>src/main/kotlin</sourceDirectory>
        <testSourceDirectory>src/test/kotlin</testSourceDirectory>
        <plugins>
            <plugin>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-plugin</artifactId>
                <version>${kotlin.version}</version>
                <executions>
                    <execution>
                        <id>compile</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                        <configuration>
                            <sourceDirs>
                                <source>src/main/kotlin</source>
                                <source>target/generated-sources/annotations</source>
                            </sourceDirs>
                        </configuration>
                    </execution>
                    <execution>
                        <id>test-compile</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>test-compile</goal>
                        </goals>
                        <configuration>
                            <sourceDirs>
                                <source>src/test/kotlin</source>
                                <source>target/generated-test-sources/test-annotations</source>
                            </sourceDirs>
                        </configuration>
                    </execution>
                </executions>
                <configuration>
                    <jvmTarget>1.8</jvmTarget>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>${maven-surefire.version}</version>
            </plugin>
            <plugin>
                <artifactId>maven-failsafe-plugin</artifactId>
                <version>${maven-surefire.version}</version>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.6.0</version>
                <configuration>
                    <mainClass>MainKt</mainClass>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.11.0</version>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-test-junit5</artifactId>
            <version>${kotlin.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter</artifactId>
            <version>${junit-jupiter.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-stdlib-jdk8</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
    </dependencies>

</project>

后续操作 #

1. 替换pom.xml为修正后的内容
2. 执行Maven命令清理并重新下载依赖：

mvn clean install -DskipTests

3. 在IntelliJ中刷新Maven依赖（点击右侧Maven面板的刷新图标）
4. 重新运行测试

内容的提问来源于stack exchange，提问作者Harsh Agarwal