* @return a new ModelSource for the resolved POM, or null if:
     *         <ul>
     *           <li>This is not a build source</li>
     *           <li>No POM can be found at the resolved location</li>
     *         </ul>
     * @throws NullPointerException if modelLocator or relative is null
     */
    @Nullable

    }

    private static class WrapModelSource implements ModelSource {
        private final org.apache.maven.model.building.ModelSource modelSource;

        WrapModelSource(org.apache.maven.model.building.ModelSource modelSource) {
            this.modelSource = modelSource;
        }

        @Override
        @Nullable
        public ModelSource resolve(@Nonnull ModelLocator modelLocator, @Nonnull String relative) {

     * in the filesystem and support resolving related POMs.
     *
     * @param path the path to the POM file or project directory
     * @return a new ModelSource instance configured as a build source
     * @throws NullPointerException if path is null
     */
    @Nonnull
    public static ModelSource buildSource(@Nonnull Path path) {
        return new BuildPathSource(requireNonNull(path, "path"));
    }

    /**

     *
     * @see org.apache.maven.model.building.ModelSource2
     */
    ProjectBuildingResult build(ModelSource modelSource, ProjectBuildingRequest request)
            throws ProjectBuildingException;

    /**
     * Builds a project descriptor for the specified model source.
     *
     * @param modelSource The source of the model to build the project descriptor from, must not be {@code null}.

        Path basePath = Paths.get("/tmp");
        ModelSource.ModelLocator locator = mock(ModelSource.ModelLocator.class);
        Path resolvedPath = Paths.get("/tmp/subproject/pom.xml");
        when(locator.locateExistingPom(any(Path.class))).thenReturn(resolvedPath);

        Sources.BuildPathSource source = (Sources.BuildPathSource) Sources.buildSource(basePath);
        ModelSource resolved = source.resolve(locator, "subproject");

import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * Test for ModelSource interface and its implementations.
 */
class ModelSourceTest {

    @Test
    void testBuildSourceHasNoModelId() {
        Path path = Paths.get("/tmp/pom.xml");
        ModelSource source = Sources.buildSource(path);

        assertNotNull(source);

        return builder(requireNonNull(request, "request cannot be null"))
                .source(requireNonNull(source, "source cannot be null"))
                .build();
    }

    @Nonnull
    static ModelBuilderRequest build(@Nonnull Session session, @Nonnull ModelSource source) {
        return builder()

import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;

import org.apache.maven.api.services.ModelBuilderException;
import org.apache.maven.api.services.ModelSource;
import org.apache.maven.artifact.DefaultArtifact;
import org.apache.maven.internal.transformation.PomArtifactTransformer;
import org.apache.maven.internal.transformation.TransformationFailedException;

            throws ModelBuilderException {
        ModelBuilderResult result = buildModel(session, src);
        Model model = result.getRawModel();
        return transformPom(model, project);
    }

    protected Model buildBomWithoutFlatten(RepositorySystemSession session, MavenProject project, ModelSource src)
            throws ModelBuilderException {

            MavenProject project, Path consumer, RepositorySystemSession session) {
        Path actual = project.getFile().toPath();
        Path parent = project.getBaseDirectory();
        ModelSource source = new ModelSource() {
            @Override
            public Path getPath() {
                return actual;
            }

            @Override
            public InputStream openStream() throws IOException {