// draw the NPE.
        project.getId();
    }

    @Test
    void testEmptyConstructor() {
        MavenProject project = new MavenProject();

        assertEquals(
                MavenProject.EMPTY_PROJECT_GROUP_ID + ":" + MavenProject.EMPTY_PROJECT_ARTIFACT_ID + ":jar:"
                        + MavenProject.EMPTY_PROJECT_VERSION,
                project.getId());
    }

    @Test

    private static final char PATH_SEPARATOR = '/';

    private static final char GROUP_SEPARATOR = '.';

    private static final char ARTIFACT_SEPARATOR = '-';

    @Override
    public String getId() {
        return "default";
    }

    @Override
    public String pathOf(Artifact artifact) {
        ArtifactHandler artifactHandler = artifact.getArtifactHandler();

        StringBuilder repos = new StringBuilder("[");

        if (localRepository != null) {
            repos.append(localRepository.getId())
                    .append(" (")
                    .append(localRepository.getBasedir())
                    .append(")");
        }

        if (remoteRepositories != null && !remoteRepositories.isEmpty()) {

                                        + ", please verify that no remote repository uses the id '"
                                        + repository.getId() + "'");
                            }
                        }
                    }
                }
            }
        } catch (Exception e) {

  interface Base {
    CharSequence getId();
  }

  interface Sub extends Base {
    @Override
    String getId();
  }

  private static class ForwardingSub implements Sub {
    private final Sub delegate;

    ForwardingSub(Sub delegate) {
      this.delegate = delegate;
    }

    @Override
    public String getId() {
      return delegate.getId();
    }

    @Override

                && a1.isOptional() == a2.isOptional();
    }

    private static int repositoryHashCode(ArtifactRepository repository) {
        int result = 17;
        result = 31 * result + (repository.getId() != null ? repository.getId().hashCode() : 0);
        return result;
    }

    private static int repositoriesHashCode(List<ArtifactRepository> repositories) {
        int result = 17;

         */
        public StemmerOverrideItem write(final StemmerOverrideItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }

        this.id = id;
        this.attributes = attributes;
    }

    /**
     * Returns the group's Security Identifier.
     * @return the group SID
     */
    public SID getId() {
        return this.id;
    }

    /**
     * Returns the group membership attributes.
     * @return the attributes value
     */
    public int getAttributes() {
        return this.attributes;
    }

            final String item1Id = item1.getId();
            if (mergedIdSet.contains(item1Id)) {
                continue;
            }

            SuggestItem mergedItem = item1;
            for (final SuggestItem item2 : items) {
                if (item1.equals(item2)) {
                    continue;
                }

                final String item2Id = item2.getId();
                if (item1Id.equals(item2Id)) {

                classifier,
                artifactHandler,
                parent.isOptional());

        setDependencyTrail(Collections.singletonList(parent.getId()));

        this.parent = parent;

        if (getId().equals(parent.getId())) {
            throw new InvalidArtifactRTException(
                    parent.getGroupId(),
                    parent.getArtifactId(),
                    parent.getVersion(),