return new StandardElementSet();
    }

    @Override
    public Iterator<T> iterator() {
      return standardIterator();
    }

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public int size() {
      return standardSize();
    }
  }

  @AndroidIncompatible // test-suite builders

    Set<MethodSignature> found = getAllFauxveridden(descendant, ancestor);
    Set<MethodSignature> missing = ImmutableSortedSet.copyOf(difference(required, found));
    if (!missing.isEmpty()) {
      fail(
          rootLocaleFormat(
              "%s should hide the public static methods declared in %s: %s",
              descendant.getSimpleName(), ancestor.getSimpleName(), missing));
    }
  }

    GeneralRange<Integer> range = GeneralRange.range(ORDERING, 2, OPEN, 4, CLOSED);
    assertTrue(range.intersect(GeneralRange.range(ORDERING, 5, CLOSED, 6, CLOSED)).isEmpty());
    assertTrue(range.intersect(GeneralRange.range(ORDERING, 1, OPEN, 2, OPEN)).isEmpty());
  }

  public void testFromRangeAll() {
    assertEquals(GeneralRange.all(Ordering.natural()), GeneralRange.from(Range.all()));
  }

        // Then
        assertNotNull(exception.getContext());
        assertTrue(exception.getContext().isEmpty());

        // Adding null context should be safe
        exception.withContext(null);
        assertTrue(exception.getContext().isEmpty());
    }

    @Test
    @DisplayName("Should be serializable")
    void testSerialization() throws Exception {
        // Given

                        // never convert from legacy to new format if either source or target is legacy format
                        if ( !v.getSnapshotVersions().isEmpty() )
                        {
                            for ( SnapshotVersion sv : versioning.getSnapshotVersions() )
                            {
                                String key = getSnapshotVersionKey( sv );

        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

        String requiredMavenVersion = pluginDescriptor.getRequiredMavenVersion();

        boolean isBlankVersion =
                requiredMavenVersion == null || requiredMavenVersion.trim().isEmpty();

        if (!isBlankVersion) {
            boolean isRequirementMet = false;
            try {
                isRequirementMet = runtimeInformation.isMavenVersion(requiredMavenVersion);