*            may be null for open end
     * @return range of versions
     */
    public static Set<DialectVersion> range ( DialectVersion min, DialectVersion max ) {
        EnumSet<DialectVersion> vers = EnumSet.noneOf(DialectVersion.class);
        for ( DialectVersion ver : values() ) {

            if ( min != null && !ver.atLeast(min) ) {
                continue;
            }

    assertEquals(0, ms.count(Color.BLUE));
    assertEquals(1, ms.count(Color.YELLOW));
    assertEquals(2, ms.count(Color.RED));
  }

  public void testIllegalCreate() {
    Collection<Color> empty = EnumSet.noneOf(Color.class);
    try {
      EnumMultiset.create(empty);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testCreateEmptyWithClass() {

    assertEquals(0, ms.count(Color.BLUE));
    assertEquals(1, ms.count(Color.YELLOW));
    assertEquals(2, ms.count(Color.RED));
  }

  public void testIllegalCreate() {
    Collection<Color> empty = EnumSet.noneOf(Color.class);
    try {
      EnumMultiset.create(empty);
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testCreateEmptyWithClass() {

    private List<ModelProblem> problems;

    private String source;

    private Model sourceModel;

    private Model rootModel;

    private Set<ModelProblem.Severity> severities = EnumSet.noneOf(ModelProblem.Severity.class);

    DefaultModelProblemCollector(ModelBuildingResult result) {
        this.result = result;
        this.problems = result.getProblems();

        getDebug().setEvents(EnumSet.allOf(TestLogEvent.class));
        getDebug().setMinGranularity(0);
        getDebug().setStackTraceFilters(EnumSet.noneOf(TestStackTraceFilter.class));
    }

    @Override
    public TestLogging getDebug() {
        return perLevelTestLogging.get(LogLevel.DEBUG);
    }

    @Override

    private List<ModelProblem> problems;

    private String source;

    private Model sourceModel;

    private Model rootModel;

    private Set<ModelProblem.Severity> severities = EnumSet.noneOf(ModelProblem.Severity.class);

    DefaultModelProblemCollector(ModelBuilderResult result) {
        this.result = result;
        this.problems = result.getProblems();

        Map<MavenArtifact, Set<ArtifactDifference>> differences = new HashMap<>();
        for (MavenArtifact mavenArtifact : mainArtifacts) {
            EnumSet<ArtifactDifference> differenceSet = EnumSet.noneOf(ArtifactDifference.class);
            if (!source.getFile().equals(mavenArtifact.getFile())) {
                differenceSet.add(ArtifactDifference.FILE);
            }