collection = getSubjectGenerator().create(arrayAndDuplicate.elements);
    E duplicate = arrayAndDuplicate.duplicate;

    int firstIndex = getList().indexOf(duplicate);
    int initialSize = getList().size();
    assertTrue("remove(present) should return true", getList().remove(duplicate));
    assertTrue(
        "After remove(duplicate), a list should still contain the duplicate element",
        getList().contains(duplicate));
    assertFalse(

  no-mergeable-selectors: 2
  no-misspelled-properties: 2
  no-qualifying-elements: 0
  no-trailing-whitespace: 2
  no-trailing-zero: 2
  no-transition-all: 0
  no-url-domains: 2
  no-url-protocols: 2
  no-warn: 2
  one-declaration-per-line: 2
  placeholder-in-extend: 2
  placeholder-name-format: 2
  property-sort-order: 0
  property-units: 2
  pseudo-element: 2
  quotes:
    - 2
    -
      style: double

checkstyle {
    toolVersion = "8.12"
    config = configFile("checkstyle.xml")
    val projectDirectory = layout.projectDirectory
    configDirectory = rules.elements.map {
        projectDirectory.dir(it.single().asFile.absolutePath).dir("checkstyle")
    }
}

plugins.withType<GroovyBasePlugin> {
    the<SourceSetContainer>().all {

      @Override
      protected Multiset<String> create(String[] elements) {
        return ConcurrentHashMultiset.create(asList(elements));
      }
    };
  }

  private static TestStringMultisetGenerator concurrentSkipListMultisetGenerator() {
    return new TestStringMultisetGenerator() {
      @Override
      protected Multiset<String> create(String[] elements) {
        Multiset<String> multiset =

  }

  private static TestStringMultisetGenerator hashMultisetGenerator() {
    return new TestStringMultisetGenerator() {
      @Override
      protected Multiset<String> create(String[] elements) {
        return HashMultiset.create(asList(elements));
      }
    };
  }

  public void testCreate() {
    Multiset<String> multiset = HashMultiset.create();
    multiset.add("foo", 2);
    multiset.add("bar");

import static org.junit.jupiter.api.Assertions.assertEquals;

/**
 * A test which demonstrates maven's recursive inheritance where
 * we are testing to make sure that elements stated in a model are
 * not clobbered by the same elements elsewhere in the lineage.
 *
 */
@Deprecated
class ProjectInheritanceTest extends AbstractProjectInheritanceTestCase {

@ElementTypesAreNonnullByDefault
class RegularImmutableList<E> extends ImmutableList<E> {
  static final ImmutableList<Object> EMPTY = new RegularImmutableList<>(new Object[0], 0);

  // The first `size` elements are non-null.
  @VisibleForTesting final transient @Nullable Object[] array;
  private final transient int size;

  RegularImmutableList(@Nullable Object[] array, int size) {
    this.array = array;
    this.size = size;

Once we have the version of the plugins the appropriate call to the plugin manager can be made to get the MojoDescriptor for the goal that needs to be run. In the MojoDescriptor we are interested in the <configuration/> element and <parameters/> element. From these elements we need to make a component configuration for the MojoExecution. The actual DOM like structure we create is of type PlexusConfiguration and is the type we use with the ComponentConfigurator to initialize fields in a Plexus...

                new TestStringSortedSetGenerator() {
                  @Override
                  protected SortedSet<String> create(String[] elements) {
                    return new StandardImplForwardingSortedSet<>(
                        new SafeTreeSet<String>(asList(elements)));
                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {

  }

  private static TestStringMultisetGenerator linkedHashMultisetGenerator() {
    return new TestStringMultisetGenerator() {
      @Override
      protected Multiset<String> create(String[] elements) {
        return LinkedHashMultiset.create(asList(elements));
      }

      @Override
      public List<String> order(List<String> insertionOrder) {
        List<String> order = Lists.newArrayList();
        for (String s : insertionOrder) {