/*
      At the moment, this class is totally immutable, and this is in line with thoughts about the
      pre-calculated execution plan that stays the same during the execution.

      If deciding to add mutable state to this class, it should be at least considered to
      separate this into a separate mutable structure.

    */

    private final List<ExecutionPlanItem> planItem;

    }

    void add(Object o) {
      checkNotNull(o);
      if (element == null) {
        this.element = o;
      } else if (extras.isEmpty()) {
        // Replace immutable empty list with mutable list.
        extras = new ArrayList<>(MAX_EXTRAS);
        extras.add(o);
      } else if (extras.size() < MAX_EXTRAS) {
        extras.add(o);
      } else {
        throw multiples(true);

 */
@NullUnmarked
public abstract class AbstractGraphTest {

  Graph<Integer> graph;

  /**
   * The same reference as {@link #graph}, except as a mutable graph. This field is null in case
   * {@link #createGraph()} didn't return a mutable graph.
   */
  MutableGraph<Integer> graphAsMutableGraph;

  static final Integer N1 = 1;
  static final Integer N2 = 2;
  static final Integer N3 = 3;

   *
   * <p>This method returns a mutable {@code List}. For an {@code ImmutableList}, use {@code
   * Resources.asCharSource(url, charset).readLines()}.
   *
   * @param url the URL to read from
   * @param charset the charset used to decode the input stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @return a mutable {@link List} containing all the lines

   *     those lists should appear in the resulting lists
   * @param <B> any common base class shared by all axes (often just {@link Object})
   * @return the Cartesian product, as an immutable list containing immutable lists
   * @throws IllegalArgumentException if the size of the cartesian product would be greater than
   *     {@link Integer#MAX_VALUE}

 * errors for using {@code get(Comparator.class)} as a {@code Comparator<Foo>}, for example.
 * Immutable empty instances are returned for collection types; {@code ""} for string; {@code 0} for
 * number types; reasonable default instance for other stateless types. For mutable types, a fresh
 * instance is created each time {@code get()} is called.
 *
 * @author Kevin Bourrillion
 * @author Ben Yu

      AvlNode<E> newRoot = new AvlNode<>(element, occurrences);
      successor(header, newRoot, header);
      rootReference.checkAndSet(root, newRoot);
      return 0;
    }
    int[] result = new int[1]; // used as a mutable int reference to hold result
    AvlNode<E> newRoot = root.add(comparator(), element, occurrences, result);
    rootReference.checkAndSet(root, newRoot);
    return result[0];
  }

  @CanIgnoreReturnValue

   * @return an immutable set containing those elements, minus duplicates
   */
  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(
      E anElement, E... otherElements) {
    return ImmutableEnumSet.asImmutable(EnumSet.of(anElement, otherElements));
  }

  /**
   * Returns an immutable set instance containing the given enum elements. Internally, the returned

        assertFalse(Features.deployBuildPom(properties)); // "0".parseBoolean() = false
    }

    @Test
    void testDeployBuildPomWithMutableMap() {
        // Test with a mutable map to ensure the method doesn't modify the input
        Map<String, Object> properties = new HashMap<>();
        properties.put(Constants.MAVEN_DEPLOY_BUILD_POM, "false");

 * errors for using {@code get(Comparator.class)} as a {@code Comparator<Foo>}, for example.
 * Immutable empty instances are returned for collection types; {@code ""} for string; {@code 0} for
 * number types; reasonable default instance for other stateless types. For mutable types, a fresh
 * instance is created each time {@code get()} is called.
 *
 * @author Kevin Bourrillion
 * @author Ben Yu