}
        if (result && os.getVersion() != null) {
            result = determineVersionMatch(os.getVersion());
        }
        return result;
    }

    private boolean ensureAtLeastOneNonNull(ActivationOS os) {
        return os.getArch() != null || os.getFamily() != null || os.getName() != null || os.getVersion() != null;
    }

    private boolean determineVersionMatch(String version) {

        return Objects.equals(a1.getGroupId(), a2.getGroupId())
                && Objects.equals(a1.getArtifactId(), a2.getArtifactId())
                && Objects.equals(a1.getVersion(), a2.getVersion());
    }

    private Properties toProperties(Map<String, String> dominant, Map<String, String> recessive) {
        Properties props = new Properties();
        if (recessive != null) {

        assertNull(artifact.getVersion());
        assertNull(artifact.getBaseVersion());
    }

    @Test
    void testMNG7780() throws Exception {
        VersionRange vr = VersionRange.createFromVersionSpec("[1.0,2.0)");
        artifact = new DefaultArtifact(groupId, artifactId, vr, scope, type, null, artifactHandler);
        assertNull(artifact.getVersion());
        assertNull(artifact.getBaseVersion());

                .version("1.0")
                .build();

        assertNotNull(this.newModelResolver().resolveModel(parent, new AtomicReference<>()));
        assertEquals("1.0", parent.getVersion());
    }

    @Test
    void testResolveParentSuccessfullyResolvesExistingParentUsingHighestVersion() throws Exception {
        final Parent parent = Parent.newBuilder()
                .groupId("ut.simple")

                boolean exists = installed.stream().map(this::getArtifactFromMap)
                        .anyMatch(a -> a.getName().equals(target.getName()) && a.getVersion().equals(target.getVersion()));
                if (!exists) {
                    ThreadUtil.sleep(500);
                    continue;
                }

        clone.setRelease(artifact.isRelease());
        clone.setResolvedVersion(artifact.getVersion());
        clone.setResolved(artifact.isResolved());
        clone.setFile(artifact.getFile());

        clone.setAvailableVersions(copyList(artifact.getAvailableVersions()));
        if (artifact.getVersion() != null) {
            clone.setBaseVersion(artifact.getBaseVersion());
        }

    }

    public String getExpandedVersion(Artifact artifact) {
        String key = getKey(artifact.getClassifier(), artifact.getExtension());
        return versions.get(key).getVersion();
    }

    @Override
    protected void merge(Metadata recessive) {
        Snapshot snapshot;
        String lastUpdated;

        if (metadata.getVersioning() == null) {

        } catch (InvalidVersionSpecificationException e) {
            result.addException(e);
            throw new VersionRangeResolutionException(result);
        }

        result.setVersionConstraint(versionConstraint);

        if (versionConstraint.getRange() == null) {
            result.addVersion(versionConstraint.getVersion());
        } else {

        // TODO Should this be changed for MNG-6754 too?
        versioning.updateTimestamp();
        versioning.addVersion(artifact.getVersion());

        if (artifact.isRelease()) {
            versioning.setRelease(artifact.getVersion());
        }

        return new ArtifactRepositoryMetadata(artifact, versioning);
    }

    @Override

        // We can do this by calling isChildOfRootNode on the current node.
        if ((artifact.getVersion() != null)
                && (!node.isChildOfRootNode() || node.getArtifact().getVersion() == null)) {
            fireEvent(ResolutionListener.MANAGE_ARTIFACT_VERSION, listeners, node, artifact);
            node.getArtifact().setVersion(artifact.getVersion());
        }

        if ((artifact.getScope() != null)