Maven Plugin Mojo Configure Default Parameter Values

Question

I have a maven plugin and a simple Mojo that looks somewhat close to

public abstract class AbstractSetupMojo extends AbstractMojo {
    @Parameter(property="targetHost", defaultValue="localhost") 
    private String targetHost;
    @Parameter(property="targetPort", defaultValue="27017")
    private Integer targetPort;
    @Parameter(property="targetDbName", required=true) 
    private String targetDbName;
    @Parameter(property="sourceHost", defaultValue="${mojo.configuration.targetHost}") 
    private String sourceHost;
    @Parameter(property="sourcePort", defaultValue="${mojo.configuration.targetPort}")
    private Integer sourcePort;
    @Parameter (property="sourceDbName", defaultValue="${mojo.configuration.targetDbName}")
    private String sourceDbName;
    @Parameter(property="scriptsPath")
    private File scriptsPath;
}     

Other Mojos are extending this one. So, the idea is to set the source* parameters to the values of the corresponding target* parameters. Also some default values are set.

In the test I have something like

public class GenerateMojoTest extends AbstractMojoTestCase {

    protected void setUp() throws Exception {
        super.setUp();
    }

    public void testConfiguration() throws Exception {
        File pom = getTestFile("src/test/resources/test-project-1/pom.xml");
        assertNotNull(pom);
        assertTrue(pom.exists());
        GenerateMojo generateMojo = (GenerateMojo)lookupMojo("generate", pom);
        assertThat(generateMojo.getSourceDbName()).isEqualTo(generateMojo.getTargetDbName());
        assertThat(generateMojo.getSourcePort()).isEqualTo(generateMojo.getTargetPort()).isEqualTo(27017);
        assertThat(generateMojo.getSourceHost()).isEqualTo(generateMojo.getTargetHost()).isEqualTo("localhost");
    }

}

The part of interest in the POM file in the test looks like

        <plugin>
            <groupId>com.ffy</groupId>
            <artifactId>setup-maven-plugin</artifactId>
    <!--                
            <configuration>
                <scriptsPath>src/test/resources/temp</scriptsPath>
            </configuration>
    -->                
            <executions>
                <execution>
                    <id>generate</id>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

The test fails because all the Mojo parameters are null if I keep <configuration> commented out, if I uncomment it then only scriptsPath is set. Other parameters are null .

Do I have to do something else in my tests in order to have a fully configured Mojo ?

I tried longer approach with

protected GenerateMojo setupMojo(final File pom) throws ComponentConfigurationException, Exception {
    final MavenExecutionRequest executionRequest = new DefaultMavenExecutionRequest();
    final ProjectBuildingRequest buildingRequest = executionRequest.getProjectBuildingRequest();
    final ProjectBuilder projectBuilder = this.lookup(ProjectBuilder.class);
    final MavenProject project = projectBuilder.build(pom, buildingRequest).getProject();
    final MavenSession session = newMavenSession(project);
    final MojoExecution execution = newMojoExecution("generate");
    final GenerateMojo mojo = (GenerateMojo) this.lookupConfiguredMojo(session, execution);
    return mojo;
}

instead of lookupMojo but that didn't change a bit.

Answer 1

You will need to have the <configuration/> part and define the values you're interested in. You would expect it to be a little smarter, but in fact what the testing harness does is, it reads the values from the <configuration/> and ignores the ones from your annotations. The testing harness leaves a lot to be desired, it doesn't actually load the values for you like a proper Maven execution/interpolation... Hence, I would advise using the maven-invoker-plugin , if it better suits your needs.