validator.validate(settings, problems);
        assertEquals(1, problems.messages.size());
        assertContains(
                problems.messages.get(0), "'servers.server.id' must be unique but found duplicate server with id test");
    }

    @Test
    void testValidateUniqueProfileId() throws Exception {
        Settings settings = new Settings();
        Profile profile1 = new Profile();

        return (depMngt != null) ? Collections.unmodifiableList(depMngt.getDependencies()) : Collections.emptyList();
    }

    // TODO: this is duplicate of PomArtifactHandlerProvider provided one
    static class PomArtifactHandler implements ArtifactHandler {
        @Override
        public String getClassifier() {
            return null;
        }

        return plugin.getDependencies();
    }

    public List<Dependency> getManagedDependencies() {
        return Collections.emptyList();
    }

    // TODO: this is duplicate of MavenPluginArtifactHandlerProvider provided one
    static class PluginArtifactHandler implements ArtifactHandler {
        @Override
        public String getClassifier() {
            return null;
        }

    //
    // 8) Create ReactorReader with the getProjectMap( projects ). NOTE that getProjectMap(projects) is the code that
    // checks for duplicate projects definitions in the build. Ideally this type of duplicate checking should be
    // part of getting the reactor projects in 6). The duplicate checking is conflated with getProjectMap(projects).
    //
    // 9) Execute AbstractLifecycleParticipant.afterProjectsRead(session)
    //

                            BuilderProblem.Severity.WARNING,
                            "servers.server.id",
                            null,
                            "must be unique but found duplicate server with id " + server.getId());
                }
            }
        }

        List<Mirror> mirrors = settings.getMirrors();

        if (mirrors != null) {

        cache.put(key, record);
        return record;
    }

    protected void assertUniqueKey(Key key) {
        if (cache.containsKey(key)) {
            throw new IllegalStateException("Duplicate artifact resolution result for project " + key);
        }
    }

    @Override
    public void flush() {
        cache.clear();
    }

    @Override

 *
 */
public interface ModelNormalizer {

    /**
     * Merges duplicate elements like multiple declarations of the same build plugin in the specified model.
     *
     * @param model The model whose duplicate elements should be merged, must not be {@code null}.
     * @param request The model building request that holds further settings, must not be {@code null}.

        }

        if (!included) {
            if (Objects.equals(winnerVersion, node.getArtifact().getVersion())) {
                details.add("omitted for duplicate");
            } else {
                details.add("omitted for conflict with " + winnerVersion);
            }
        }

        StringBuilder buffer = new StringBuilder();
        if (included) {

        PomTestWrapper pom = buildPom( "dependency-scope/sub" );

    }*/

    /*MNG- 4010*/
    @Test
    void testDuplicateExclusionsDependency() throws Exception {
        PomTestWrapper pom = buildPom("duplicate-exclusions-dependency/sub");
        assertEquals(1, ((List<?>) pom.getValue("dependencies[1]/exclusions")).size());
    }

    /*MNG- 4008*/
    @Test
    void testMultipleFilters() throws Exception {

 files for the current project. if yes. then I'm able to find projects that
 can be offered to be opened together with the current project.
 problems with the current solution are:
 1. information is duplicate. once in POM's dependencies and once in the
 maven.multiproject.includes property.
 2. it works without problems only for projects with relative paths, e.g., from