<configuration>
          <defaults>
            <parent>child</parent>
            <child>child</child>
          </defaults>
          <appends combine.children="append">
            <parent>child</parent>
            <child>child</child>
          </appends>
          <overrides combine.self="override">
            <parent>child</parent>
            <child>child</child>
          </overrides>

        assertTrue(exception.getMessage().contains("invalid"));
        verify(treeHandle, never()).acquire();
    }

    @Test
    @DisplayName("Constructor should handle null parent")
    void testConstructor_NullParent_ThrowsNPE() {
        // When & Then: Null parent should cause NullPointerException

        final List<Vertex> parents = new ArrayList<>();

        Vertex(String label) {
            this.label = label;
        }

        String getLabel() {
            return label;
        }

        List<Vertex> getChildren() {
            return children;
        }

        List<Vertex> getParents() {
            return parents;
        }
    }

    }

    @Test
    void testIdentityProtoInheritance() {
        Parent parent = new Parent();

        parent.setGroupId("test-group");
        parent.setVersion("1000");
        parent.setArtifactId("test-artifact");

        Model model = new Model();

        model.setParent(parent);
        model.setArtifactId("real-artifact");

        MavenProject project = new MavenProject(model);

        final List<Vertex> parents = new ArrayList<>();

        Vertex(String label) {
            this.label = label;
        }

        String getLabel() {
            return label;
        }

        List<Vertex> getChildren() {
            return children;
        }

        List<Vertex> getParents() {
            return parents;
        }
    }

    /**
     * The version of the extension.
     */
    private String version;

    /**
     * The class loading strategy: 'self-first' (the default),
     * 'parent-first' (loads classes from the parent, then from the
     * extension) or 'plugin' (follows the rules from extensions
     * defined as plugins).
     */
    private String classLoadingStrategy = "self-first";

    // -----------/

     * </p>
     *
     * @param parent The parent coordinates to resolve, must not be {@code null}.
     *
     * @return The source of the requested POM, never {@code null}.
     *
     * @throws UnresolvableModelException If the POM could not be resolved from any configured repository.
     * @since 3.2.2
     *
     * @see Parent#clone()
     */

        restore-keys: |
          ${{ runner.os }}-maven-
    - name: Checkout fess-parent
      uses: actions/checkout@v4
      with:
        repository: codelibs/fess-parent
        ref: ${{ env.PARENT_BRANCH }}
        path: fess-parent
    - name: Install fess-parent
      run: |
        cd fess-parent
        mvn install -Dgpg.skip=true
    - name: Build with Maven

    private final ResourceFilter filter;
    private final SmbResource parent;
    private SmbResource next;

    /**
     * @param parent
     * @param delegate
     * @param filter
     *
     */
    public FileEntryAdapterIterator(final SmbResource parent, final CloseableIterator<FileEntry> delegate, final ResourceFilter filter) {
        this.parent = parent;
        this.delegate = delegate;
        this.filter = filter;

    </description>
  </expression>
  <expression>
    <syntax>project.parent</syntax>
    <configuration>
      <![CDATA[
<parent>
  <groupId>project.group</groupId>
  <artifactId>project-artifact</artifactId>
  <version>0.0.0.0</version>
</parent>
    ]]></configuration>
    <description> This is the MavenProject instance for the parent of the current POM.
    </description>
  </expression>
  <expression>