maven-plugin-testing-harness/src/site/apt/examples/repositories.apt

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 Testing Using Repositories
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 Vincent Siveton
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 February 2008
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~~ "License"); you may not use this file except in compliance
~~ with the License.  You may obtain a copy of the License at
~~
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~~
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~~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
~~ KIND, either express or implied.  See the License for the
~~ specific language governing permissions and limitations
~~ under the License.

Testing Using Repositories

 <<Note>>: This example improves the {{{../getting-started/index.html}cookbook}} for testing repositories.

 When developing a Maven plugin you often need to play with repositories. Suppose that the MyMojo needs
 to download artifacts into your local repository, i.e.:

+----+
public class MyMojo
    extends AbstractMojo
{
    /**
     * Used for resolving artifacts
     */
    @Component
    private ArtifactResolver resolver;

    /**
     * Factory for creating artifact objects
     */
    @Component
    private ArtifactFactory factory;

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

    public void execute()
        throws MojoExecutionException
    {
        ...

        Artifact artifact = factory.createArtifact( "junit", "junit", "3.8.1", "compile", "jar" );
        try
        {
            resolver.resolve( artifact, project.getRemoteArtifactRepositories(), localRepository );
        }
        catch ( ArtifactResolutionException e )
        {
            throw new MojoExecutionException( "Unable to resolve artifact:" + artifact, e );
        }
        catch ( ArtifactNotFoundException e )
        {
            throw new MojoExecutionException( "Unable to find artifact:" + artifact, e );
        }

        ...
     }
}
+----+

* Create Stubs

 Stub for the test project:

+----+
public class MyProjectStub
    extends MavenProjectStub
{
    /**
     * Default constructor
     */
    public MyProjectStub()
    {
        ...
    }

    /** {@inheritDoc} */
    public List getRemoteArtifactRepositories()
    {
        ArtifactRepository repository = new DefaultArtifactRepository( "central", "http://repo.maven.apache.org/maven2",
                                                                       new DefaultRepositoryLayout() );

        return Collections.singletonList( repository );
    }
}
+----+

* Configure <<<project-to-test>>> pom

+----+
<project>
  ...
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-my-plugin</artifactId>
        <configuration>
          <!-- Specify where this pom will output files -->
          <outputDirectory>${basedir}/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 stub -->
          <project implementation="org.apache.maven.plugin.my.stubs.MyProjectStub"/>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>
+----+

** Execute test

 Calling <<<mvn test>>> will create <<<$\{basedir\}/target/local-repo/junitjunit/3.8.1/junit-3.8.1.jar>>> file.