* undirected edges connect a pair of nodes to each other.
   */
  @Override
  boolean isDirected();

  /**
   * Returns true if this graph allows self-loops (edges that connect a node to itself). Attempting
   * to add a self-loop to a graph that does not allow them will throw an {@link
   * IllegalArgumentException}.
   */
  @Override
  boolean allowsSelfLoops();

    void setValue(E entry, V value) {
      this.map.entryHelper.setValue(self(), entry, value);
    }

    /** Returns a copy of the given {@code entry}. */
    @CheckForNull
    E copyEntry(E original, E newNext) {
      return this.map.entryHelper.copy(self(), original, newNext);
    }

    AtomicReferenceArray<E> newEntryArray(int size) {

                    checkArgument(elements.length == 1);
                    return Sets.union(Sets.<String>newHashSet(elements), Sets.newHashSet(elements));
                  }
                })
            .named("singleton U itself")
            .withFeatures(CollectionSize.ONE, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(
                new TestStringSetGenerator() {

  protected B usingGenerator(G subjectGenerator) {
    this.subjectGenerator = subjectGenerator;
    return self();
  }

  public G getSubjectGenerator() {
    return subjectGenerator;
  }

  @CanIgnoreReturnValue
  public B withSetUp(Runnable setUp) {
    this.setUp = setUp;
    return self();
  }

  public Runnable getSetUp() {
    return setUp;
  }

  @CanIgnoreReturnValue

    return new HashMultiset<>(distinctElements);
  }

  /**
   * Creates a new {@code HashMultiset} containing the specified elements.
   *
   * <p>This implementation is highly efficient when {@code elements} is itself a {@link Multiset}.
   *
   * @param elements the elements that the multiset should contain
   */
  public static <E extends @Nullable Object> HashMultiset<E> create(
      Iterable<? extends E> elements) {

import org.apache.maven.project.MavenProject;

/**
 * A facade that provides lifecycle services to components outside maven core.
 * <p>
 * Note that this component is not normally used from within core itself.
 *
 */
@Named
@Singleton
public class DefaultLifecycleExecutor implements LifecycleExecutor {

    private final LifeCyclePluginAnalyzer lifeCyclePluginAnalyzer;

    assertTrue("addAll(n, containsNull) should return true", getList().addAll(0, containsNull));
    /*
     * We need (E) to force interpretation of null as the single element of a
     * varargs array, not the array itself
     */
    expectAdded(0, (E) null);
  }

  @ListFeature.Require(SUPPORTS_ADD_WITH_INDEX)
  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
  public void testAddAllAtIndex_nullUnsupported() {

      fail("No exception thrown");
    } catch (Exception e) {
      if (!(e instanceof SomeCheckedException)) {
        throw e;
      }
    }

    // But the second time, AbstractIterator itself throws an ISE
    try {
      iter.hasNext();
      fail("No exception thrown");
    } catch (IllegalStateException expected) {
    }
  }

  public void testException() {

   * @param self a collection which might contain all elements in {@code c}
   * @param c a collection whose elements might be contained by {@code self}
   */
  static boolean containsAllImpl(Collection<?> self, Collection<?> c) {
    for (Object o : c) {
      if (!self.contains(o)) {
        return false;
      }
    }
    return true;
  }

  /** An implementation of {@link Collection#toString()}. */

  // here too.
  static final String ERROR_MODIFIABLE_SET = "Set returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";

  /** Creates and returns an instance of the graph to be tested. */
  abstract Graph<Integer> createGraph();

  /**