使用maven-plugin-testing-harness测试Maven插件

Question

我想开发一个Maven插件，并且还要测试它。我正在阅读maven-plugin-testing-harness上的文档并尝试了几个小时。我经常遇到NoClassDefFoundError和NoSuchMethodError，我无法弄清楚我需要哪些依赖项。

这是我的MCVE：

https://github.com/highsource/hello-maven-plugin

现在我得到了：

java.lang.NoClassDefFoundError: org/apache/maven/plugin/descriptor/PluginDescriptorBuilder
    at org.apache.maven.plugin.testing.AbstractMojoTestCase.setUp(AbstractMojoTestCase.java:161)
    at junit.framework.TestCase.runBare(TestCase.java:139)
    at junit.framework.TestResult$1.protect(TestResult.java:122)
    at junit.framework.TestResult.runProtected(TestResult.java:142)
    at junit.framework.TestResult.run(TestResult.java:125)
    at junit.framework.TestCase.run(TestCase.java:129)
    at junit.framework.TestSuite.runTest(TestSuite.java:255)
    at junit.framework.TestSuite.run(TestSuite.java:250)
    at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:84)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.lang.ClassNotFoundException: org.apache.maven.plugin.descriptor.PluginDescriptorBuilder
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 15 more

这是我的插件pom.xml：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.hisrc.storyteller</groupId>
    <artifactId>storyteller-maven-plugin</artifactId>
    <packaging>maven-plugin</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>storyteller-maven-plugin Maven Mojo</name>
    <dependencies>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-plugin-api</artifactId>
            <version>2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-core</artifactId>
            <version>3.3.9</version>
        </dependency>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-artifact</artifactId>
            <version>3.3.9</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-compat</artifactId>
            <version>3.3.9</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.maven.plugin-testing</groupId>
            <artifactId>maven-plugin-testing-harness</artifactId>
            <scope>test</scope>
            <version>3.3.0</version>
        </dependency>
    </dependencies>
</project>

MyMojo.java是微不足道的：

/**
 * Goal which touches a timestamp file.
 *
 * @goal touch
 * 
 * @phase process-sources
 */
public class MyMojo extends AbstractMojo {
    /**
     * Location of the file.
     * 
     * @parameter expression="${project.build.directory}"
     * @required
     */
    private File outputDirectory;

    public void execute() throws MojoExecutionException {
        // Simply creates a touch.txt file in outputDirectory
    }
}

测试：

public class MyMojoTest extends AbstractMojoTestCase {

    @Test
    public void testSomething()
        throws Exception
    {
        File pom = getTestFile( "src/test/resources/org/hisrc/storyteller/pom.xml" );
        assertNotNull( pom );
        assertTrue( pom.exists() );

        MyMojo myMojo = (MyMojo) lookupMojo( "touch", pom );
        assertNotNull( myMojo );
        myMojo.execute();
    }
}

pom.xml进行测试：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    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>

    <groupId>org.hisrc.storyteller</groupId>
    <artifactId>project-to-test</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>Test MyMojo</name>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>storyteller-maven-plugin</artifactId>
                <configuration>
                    <outputDirectory>target/test-harness/project-to-test</outputDirectory>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

如果我将maven-plugin-api的版本更改为3.0，我就会：

java.lang.NoSuchMethodError: org.codehaus.plexus.ContainerConfiguration.setClassPathScanning(Ljava/lang/String;)Lorg/codehaus/plexus/ContainerConfiguration;
    at org.apache.maven.plugin.testing.AbstractMojoTestCase.setupContainerConfiguration(AbstractMojoTestCase.java:285)
    at org.apache.maven.plugin.testing.AbstractMojoTestCase.setupContainer(AbstractMojoTestCase.java:259)
    at org.apache.maven.plugin.testing.AbstractMojoTestCase.getContainer(AbstractMojoTestCase.java:298)
    at org.apache.maven.plugin.testing.AbstractMojoTestCase.setUp(AbstractMojoTestCase.java:152)
    at junit.framework.TestCase.runBare(TestCase.java:139)
    at junit.framework.TestResult$1.protect(TestResult.java:122)
    at junit.framework.TestResult.runProtected(TestResult.java:142)
    at junit.framework.TestResult.run(TestResult.java:125)
    at junit.framework.TestCase.run(TestCase.java:129)
    at junit.framework.TestSuite.runTest(TestSuite.java:255)
    at junit.framework.TestSuite.run(TestSuite.java:250)
    at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:84)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

我环顾四周，我看到的只是人们似乎添加了一些随机的依赖关系，有时事情有时不起作用。我花了几个小时试图做同样的事情，但没有设法让它发挥作用。我此刻非常绝望，并希望有人最终弄清楚它并指出我正确的依赖关系和/或版本。

Answer 1

@FlorianAlbrecht是对的，我必须为Maven依赖项指定相同的版本（3.3.9）。这就是我最终的结果：

<properties>
    <maven.version>3.3.9</maven.version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.apache.maven.plugin-tools</groupId>
        <artifactId>maven-plugin-annotations</artifactId>
        <version>3.5</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-plugin-api</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-core</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-artifact</artifactId>
        <version>${maven.version}</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.maven</groupId>
        <artifactId>maven-compat</artifactId>
        <version>${maven.version}</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.maven.plugin-testing</groupId>
        <artifactId>maven-plugin-testing-harness</artifactId>
        <scope>test</scope>
        <version>3.3.0</version>
    </dependency>
</dependencies>