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Testing Complex Mojo Parameters

Note: This example improves the cookbook for testing complex Mojo parameters.

In real plugin development, you will use specific Maven objects like MavenProject, ArtifactRepository or MavenSettings. You could use them by defining stubs.

Suppose that you have the following dependencies in the maven-my-plugin pom:

<project>
  ...
  <dependencies>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-artifact</artifactId>
      <version>2.0.8</version>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-project</artifactId>
      <version>2.0.8</version>
    </dependency>
    ...
  </dependencies>
</project>

You will add the following in the MyMojo:

public class MyMojo
    extends AbstractMojo
{
    /**
     * The Maven Project.
     */
    @Parameter( defaultValue = "${project}", readonly = true )
    protected MavenProject project;

    /**
     * Local Repository.
     */
    @Parameter( defaultValue = "${localRepository}", readonly = true, required = true )
    protected ArtifactRepository localRepository;

    /**
     * The Maven Settings.
     */
    @Parameter( defaultValue = "${settings}", readonly = true )
    private Settings settings;

    ...
}

Create Stubs

You need to create stub objects to run MyMojoTest#testSomething(). By convention, the package name should reflect the stubs, i.e. in our case org.apache.maven.plugin.my.stubs.

public class MyProjectStub
    extends MavenProjectStub
{
    /**
     * Default constructor
     */
    public MyProjectStub()
    {
        MavenXpp3Reader pomReader = new MavenXpp3Reader();
        Model model;
        try
        {
            model = pomReader.read( ReaderFactory.newXmlReader( new File( getBasedir(), "pom.xml" ) ) );
            setModel( model );
        }
        catch ( Exception e )
        {
            throw new RuntimeException( e );
        }

        setGroupId( model.getGroupId() );
        setArtifactId( model.getArtifactId() );
        setVersion( model.getVersion() );
        setName( model.getName() );
        setUrl( model.getUrl() );
        setPackaging( model.getPackaging() );

        Build build = new Build();
        build.setFinalName( model.getArtifactId() );
        build.setDirectory( getBasedir() + "/target" );
        build.setSourceDirectory( getBasedir() + "/src/main/java" );
        build.setOutputDirectory( getBasedir() + "/target/classes" );
        build.setTestSourceDirectory( getBasedir() + "/src/test/java" );
        build.setTestOutputDirectory( getBasedir() + "/target/test-classes" );
        setBuild( build );

        List compileSourceRoots = new ArrayList();
        compileSourceRoots.add( getBasedir() + "/src/main/java" );
        setCompileSourceRoots( compileSourceRoots );

        List testCompileSourceRoots = new ArrayList();
        testCompileSourceRoots.add( getBasedir() + "/src/test/java" );
        setTestCompileSourceRoots( testCompileSourceRoots );
    }

    /** {@inheritDoc} */
    public File getBasedir()
    {
        return new File( super.getBasedir() + "/src/test/resources/unit/project-to-test/" );
    }
}
public class SettingsStub
    extends Settings
{
    /** {@inheritDoc} */
    public List getProxies()
    {
        return Collections.EMPTY_LIST;
    }
}

Configure project-to-test pom

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-my-plugin</artifactId>
        <configuration>
          <!-- Specify where this pom will output files -->
          <outputDirectory>target/test-harness/project-to-test</outputDirectory>

          <!-- By default <<<${basedir}/target/local-repo", where basedir refers
               to the basedir of maven-my-plugin. -->
          <localRepository>${localRepository}</localRepository>
          <!-- The defined stubs -->
          <project implementation="org.apache.maven.plugin.my.stubs.MyProjectStub"/>
          <settings implementation="org.apache.maven.plugin.my.stubs.SettingsStub"/>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>