}
            return buf.toString();
        }
    }

    public ArtifactVersion matchVersion(List<ArtifactVersion> versions) {
        // TODO could be more efficient by sorting the list and then moving along the restrictions in order?

        ArtifactVersion matched = null;
        for (ArtifactVersion version : versions) {
            if (containsVersion(version)) {

    }

    @Override
    public boolean isRelease() {
        return release;
    }

    @Override
    public List<ArtifactVersion> getAvailableVersions() {
        return availableVersions;
    }

    @Override
    public void setAvailableVersions(List<ArtifactVersion> availableVersions) {
        this.availableVersions = availableVersions;
    }

    @Override
    public boolean isOptional() {

import org.apache.maven.artifact.metadata.ArtifactMetadataSource;
import org.apache.maven.artifact.metadata.ResolutionGroup;
import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.versioning.ArtifactVersion;
import org.apache.maven.repository.legacy.metadata.MetadataResolutionRequest;
import org.eclipse.aether.DefaultRepositorySystemSession;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
import org.apache.maven.artifact.resolver.filter.ExclusionArtifactFilter;
import org.apache.maven.artifact.versioning.ArtifactVersion;
import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
import org.apache.maven.artifact.versioning.InvalidVersionSpecificationException;
import org.apache.maven.artifact.versioning.VersionRange;

                                    // transformation?
                                    ArtifactVersion version;
                                    if (!artifact.isSelectedVersionKnown()) {
                                        List<ArtifactVersion> versions = artifact.getAvailableVersions();
                                        if (versions == null) {

            List<ArtifactVersion> artifactVersions = versions.computeIfAbsent(key, k -> new ArrayList<>());
            if (spec.artifact.getVersion() != null) {
                artifactVersions.add(new DefaultArtifactVersion(spec.artifact.getVersion()));
            }
        }

        public List<ArtifactVersion> retrieveAvailableVersions(

                "Version " + version + " should have failed to construct");
    }

    @Test
    void testContains() throws InvalidVersionSpecificationException {
        ArtifactVersion actualVersion = new DefaultArtifactVersion("2.0.5");
        assertTrue(enforceVersion("2.0.5", actualVersion));
        assertTrue(enforceVersion("2.0.4", actualVersion));