for (E e : set2) {
          if (!set1.contains(e)) {
            size++;
          }
        }
        return size;
      }

      @Override
      public boolean isEmpty() {
        return set1.isEmpty() && set2.isEmpty();
      }

      @Override
      public UnmodifiableIterator<E> iterator() {
        return new AbstractIterator<E>() {
          final Iterator<? extends E> itr1 = set1.iterator();

        for (Plugin plugin : plugins) {
            if (plugin.getGroupId() == null
                    || (plugin.getGroupId() != null
                            && plugin.getGroupId().trim().isEmpty())) {
                addViolation(
                        problems,
                        Severity.FATAL,
                        Version.V20,
                        prefix + prefix2 + "(groupId:artifactId)",

        System.out.println("Project " + project1.getId() + " " + project1);
        Set set = project1.getArtifacts();
        assertNotNull(set, "No artifacts");
        assertFalse(set.isEmpty(), "No Artifacts");
        assertTrue(set.size() == 3, "Set size should be 3, is " + set.size());

        for (Object aSet : set) {
            Artifact artifact = (Artifact) aSet;

    val mainMethod =
      Class
        .forName(className)
        .methods
        .find { it.name == "main" }
    try {
      if (mainMethod != null) {
        if (mainMethod.parameters.isEmpty()) {
          mainMethod.invoke(null)
        } else {
          mainMethod.invoke(null, arrayOf<String>())
        }
      } else {
        System.err.println("No main for $className")
      }

 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public class MoreCollectorsTest extends TestCase {
  public void testToOptionalEmpty() {
    assertThat(Stream.empty().collect(toOptional())).isEmpty();
  }

  public void testToOptionalSingleton() {
    assertThat(Stream.of(1).collect(toOptional())).hasValue(1);
  }

  public void testToOptionalNull() {

    public MavenExecutionResult addException(Throwable t) {
        exceptions.add(t);

        return this;
    }

    @Override
    public boolean hasExceptions() {
        return !getExceptions().isEmpty();
    }

    @Override
    public BuildSummary getBuildSummary(MavenProject project) {
        return buildSummaries.get(project);
    }

    @Override

 * may be equal only if at least one of the bounds is closed:
 *
 * <ul>
 *   <li>{@code [a..a]} : a singleton range
 *   <li>{@code [a..a); (a..a]} : {@linkplain #isEmpty empty} ranges; also valid
 *   <li>{@code (a..a)} : <b>invalid</b>; an exception will be thrown
 * </ul>
 *
 * <h3>Warnings</h3>
 *
 * <ul>

                    .append(" (")
                    .append(localRepository.getBasedir())
                    .append(")");
        }

        if (remoteRepositories != null && !remoteRepositories.isEmpty()) {
            for (RemoteRepository repository : remoteRepositories) {
                repos.append(", ");

                if (repository != null) {
                    repos.append(repository.getId())

    MavenArtifact(String repositoryUrl, Resource resource) {
        if (repositoryUrl == null) {
            this.repositoryUrl = "";
        } else if (!repositoryUrl.endsWith("/") && !repositoryUrl.isEmpty()) {
            this.repositoryUrl = repositoryUrl + '/';
        } else {
            this.repositoryUrl = repositoryUrl;
        }
        this.resource = resource;

    private static final String WORKSPACE = "WORKSPACE";

    @Override
    public Optional<CIInfo> detectCI() {
        String workspace = System.getenv(WORKSPACE);
        if (workspace != null && !workspace.trim().isEmpty()) {
            return Optional.of(new CIInfo() {
                @Override
                public String name() {
                    return NAME;
                }
            });
        }