* @return The resolved plugin artifact, never {@code null}.
     * @throws PluginResolutionException If the plugin artifact could not be resolved.
     */
    Artifact resolve(Plugin plugin, List<RemoteRepository> repositories, RepositorySystemSession session)
            throws PluginResolutionException;

    /**

                "Expected 'ModelResolverException' not thrown.");
        assertNotNull(e.getMessage());
        assertThat(e.getMessage(), containsString("Could not find artifact org.apache:apache:pom:0 in central"));
    }

    @Test
    void testResolveParentThrowsModelResolverExceptionWhenNoMatchingVersionFound() throws Exception {
        final Parent parent = Parent.newBuilder()

    Path getTopDirectory();

    /**
     * Gets the root directory of the session, which is the root directory for the top directory project.
     *
     * @throws IllegalStateException if the root directory could not be found
     * @see #getTopDirectory()
     * @see Project#getRootDirectory()
     */
    @Nonnull
    Path getRootDirectory();

    @Nonnull
    List<Project> getProjects();

    /**

            configuratorId = mojoDescriptor.isV4Api() ? "enhanced" : "basic";
        }

        try {
            // TODO could the configuration be passed to lookup and the configurator known to plexus via the descriptor
            // so that this method could entirely be handled by a plexus lookup?
            configurator = container.lookup(ComponentConfigurator.class, configuratorId);

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

// It would be cool if there was a hook that I could use to set up a test environment.
// I want to set up a local/remote repositories for testing but I don't want to have
// to change them when I change the layout of the repositories. So I want to generate

        ExecutorService createExecutor(int parallelism) {
            //
            // We need an executor that will not block.
            // We can't use work stealing, as we are building a graph
            // and this could lead to cycles where a thread waits for
            // a task to finish, then execute another one which waits
            // for the initial task...
            // In order to work around that problem, we override the

     * @param modified a holder for the updated parent, must not be {@code null}.
     * @return The source of the requested POM, never {@code null}.
     * @throws ModelResolverException If the POM could not be resolved from any configured repository.
     */
    @Nonnull
    default ModelSource resolveModel(
            @Nonnull Session session, @Nonnull Parent parent, @Nonnull AtomicReference<Parent> modified)

            return new MetadataStaxReader().read(input, false);
        } catch (IOException | XMLStreamException e) {
            throw new RepositoryException("Could not parse metadata " + metadataPath + ": " + e.getMessage(), e);
        }
    }

    private void write(Path metadataPath, Metadata metadata) throws RepositoryException {
        try {

                String name = active.getName();
                boolean daemon = active.isDaemon();
                assertTrue(daemon, name + " is no daemon Thread.");
            }
        }

        assertTrue(seen, "Could not find ThreadGroup: " + DefaultArtifactResolver.DaemonThreadCreator.THREADGROUP_NAME);
    }

    @Test
    void testLookup() throws Exception {

                        .twoPhaseBuilding(false)
                        .source(ModelSource.fromPath(pomArtifact.getPath(), gav))
                        // This merge is on purpose because otherwise user properties would override model
                        // properties in dependencies the user does not know. See MNG-7563 for details.
                        .systemProperties(toProperties(session.getUserProperties(), session.getSystemProperties()))