</plugin>
      <plugin>
        <artifactId>maven-source-plugin</artifactId>
      </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>animal-sniffer-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <extensions>true</extensions>
        <groupId>org.apache.felix</groupId>
        <artifactId>maven-bundle-plugin</artifactId>
        <version>6.0.0</version>

    }

    private Plugin createPlugin(String groupId, String artifactId, String version) {
        Plugin plugin = new Plugin();
        plugin.setGroupId(groupId);
        plugin.setArtifactId(artifactId);
        plugin.setVersion(version);
        return plugin;
    }

    private Extension createExtension(String groupId, String artifactId, String version) {
        Extension extension = new Extension();

        <artifactId>toolchains-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <artifactId>maven-toolchains-plugin</artifactId>
      </plugin>
      <plugin>
        <artifactId>maven-jar-plugin</artifactId>
      </plugin>
      <plugin>
        <extensions>true</extensions>
        <groupId>org.apache.felix</groupId>
        <artifactId>maven-bundle-plugin</artifactId>

      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-annotations</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-xml</artifactId>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.modello</groupId>
        <artifactId>modello-maven-plugin</artifactId>
        <configuration>

      <artifactId>maven-api-model</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-api-xml</artifactId>
    </dependency>

    <!-- Maven4 impl -->
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-core</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-cli</artifactId>

        DomUtils.addGAVElements(dependency2, "org.example", "test-artifact2", null);

        xmlOutput = DomUtils.toXml(doc);
        assertTrue(xmlOutput.contains("<artifactId>test-artifact2</artifactId>"), "Should contain second artifactId");
        assertFalse(
                xmlOutput.contains("test-artifact2</artifactId>\n        <version>"),
                "Should not add version element for null version");

    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-jline</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-logging</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.maven</groupId>
      <artifactId>maven-xml</artifactId>
    </dependency>

    <!-- compat -->

        <artifactId>guava</artifactId>
        <version>${project.version}</version>
      </dependency>
      <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava-gwt</artifactId>
        <version>${project.version}</version>
      </dependency>
      <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava-testlib</artifactId>

 the Maven Repository Metadata file contains 3 different sets of metadata:

 [[1]] in a "groupId" directory: a "groupId" directory may contain Maven plugins artifacts, which are described in metadata's <<<plugins>>> element,

 [[2]] in a "groupId/artifactId" directory: metadata describes <<<groupId>>>, <<<artifactId>>> and <<<versioning>>> element that

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-source-plugin</artifactId>
      </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>animal-sniffer-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <artifactId>maven-javadoc-plugin</artifactId>
        <executions>
          <execution>
            <id>attach-javadocs</id>
          </execution>