newComparable("0-x");
        newComparable("0.rc");
        newComparable("0-1");

        ComparableVersion version = new ComparableVersion("0.x");
        assertEquals("x", version.getCanonical());
        ComparableVersion version2 = new ComparableVersion("0.2");
        assertEquals("0.2", version2.getCanonical());
    }

    /**
     * Test <a href="https://issues.apache.org/jira/browse/MNG-5568">MNG-5568</a> edge case

                versioning.release(recessive.getVersioning().getRelease());
            }

            Collection<String> versions =
                    new LinkedHashSet<>(recessive.getVersioning().getVersions());
            versions.addAll(original.getVersions());
            versioning.versions(new ArrayList<>(versions));
        }

        metadata = metadata.withVersioning(versioning.build());

        // just carry-on as-is

    }

    public List<ArtifactVersion> retrieveAvailableVersionsFromDeploymentRepository(
            Artifact artifact, ArtifactRepository localRepository, ArtifactRepository remoteRepository)
            throws ArtifactMetadataRetrievalException {
        throw new UnsupportedOperationException("Cannot get available versions in this test case");
    }

        } else {
            changed = metadata.merge(this.metadata);
        }

        // beware meta-versions!
        String version = metadata.getVersion();
        if (Artifact.LATEST_VERSION.equals(version) || Artifact.RELEASE_VERSION.equals(version)) {
            // meta-versions are not valid <version/> values...don't write them.
            metadata.setVersion(null);
        }

                () -> newModelResolver().resolveModel(parent.getDelegate(), new AtomicReference<>()),
                "Expected 'UnresolvableModelException' not thrown.");
        assertEquals("No versions matched the requested parent version range '[2.0,2.1)'", e.getMessage());
    }

    @Test
    void testResolveParentThrowsUnresolvableModelExceptionWhenUsingRangesWithoutUpperBound() throws Exception {

        }

        for (String key : versions.keySet()) {
            if (versions.get(key) == null && managedVersions.get(key) == null) {
                InputLocation location = plugins.get(key).getLocation("");
                problems.add(
                        Severity.WARNING,
                        ModelProblem.Version.V20,
                        "'build.plugins.plugin.version' for " + key + " is missing.",

     *         of this version range and the specified version range if both version ranges have
     *         restrictions. Otherwise, the restrictions on the returned range will be empty.
     *         </p>
     *         <p>
     *         The recommended version of the returned version range will be the recommended version of
     *         this version range, provided that ranges falls within the intersected restrictions. If

                .version("[2.0,2.1)")
                .build();

        ModelResolverException e = assertThrows(
                ModelResolverException.class,
                () -> newModelResolver().resolveModel(session, parent, new AtomicReference<>()),
                "Expected 'ModelResolverException' not thrown.");
        assertEquals("No versions matched the requested version range '[2.0,2.1)'", e.getMessage());
    }

import java.util.List;

import org.apache.maven.api.Service;
import org.apache.maven.api.model.Model;

public interface ModelBuilder extends Service {

    List<String> VALID_MODEL_VERSIONS = List.of("4.0.0", "4.1.0");

    ModelBuilderResult build(ModelBuilderRequest request) throws ModelBuilderException;

    ModelTransformerContextBuilder newTransformerContextBuilder();

 */
@Named(VersionsMetadataGeneratorFactory.NAME)
@Singleton
public class VersionsMetadataGeneratorFactory implements MetadataGeneratorFactory {
    public static final String NAME = "versions";

    @Override
    public MetadataGenerator newInstance(RepositorySystemSession session, InstallRequest request) {
        return new VersionsMetadataGenerator(session, request);
    }

    @Override