return requireNonNull(predecessor);
  }

  private int[] requireSuccessors() {
    return requireNonNull(successor);
  }

  /*
   * We don't define getPredecessor+getSuccessor and setPredecessor+setSuccessor here because
   * they're defined above -- including logic to add and subtract 1 to map between the values stored
   * in the predecessor/successor arrays and the indexes in the elements array that they identify.
   */

                        + "stub-plugin-test, "
                        + "stub-plugin-package, "
                        + "stub-plugin-install], "
                        + "you should define versions in pluginManagement section of your pom.xml or parent");
    }

    @Test
    void testHandleBuildError() throws Exception {}

    @Test
    void testAttachToThread() throws Exception {}

    @Test

     *
     * That combination upsets NullPointerTester, which wants any call that passes null for a
     * non-@Nullable parameter to trigger a NullPointerException.
     *
     * (We still define this empty method to keep PackageSanityTests from generating its own
     * automated nullness tests, which would fail.)
     */
  }

  private static final Object IGNORE_ME =
      new Object() {

    assertThat(networkA.edgeOrder()).isEqualTo(networkB.edgeOrder());

    assertThat(networkA).isEqualTo(networkB);
  }

  /**
   * In some cases our graph implementations return custom sets that define their own size() and
   * contains(). Verify that these sets are consistent with the elements of their iterator.
   */
  @CanIgnoreReturnValue
  static <T> Set<T> sanityCheckSet(Set<T> set) {

    assertThat(networkA.edgeOrder()).isEqualTo(networkB.edgeOrder());

    assertThat(networkA).isEqualTo(networkB);
  }

  /**
   * In some cases our graph implementations return custom sets that define their own size() and
   * contains(). Verify that these sets are consistent with the elements of their iterator.
   */
  @CanIgnoreReturnValue
  static <T> Set<T> sanityCheckSet(Set<T> set) {

      return delegate.create(elements);
    }

    @Override
    public Entry<K, V>[] createArray(int length) {
      return delegate.createArray(length);
    }
  }

  /** Two bounds (from and to) define how to build a subMap. */
  public enum Bound {
    INCLUSIVE,
    EXCLUSIVE,
    NO_BOUND;
  }

  public static class SortedSetSubsetTestSetGenerator<E extends @Nullable Object>

    // vol. 2, Knuth, 4.2.2, (16) to the two-variable case. We have two value series x_i and y_i.
    // We define the arithmetic means X_n = 1/n \sum_{i=1}^n x_i, and Y_n = 1/n \sum_{i=1}^n y_i.
    // We also define the sum of the products of the differences from the means
    //           C_n = \sum_{i=1}^n x_i y_i - n X_n Y_n
    // for all n >= 1. Then for all n > 1:

   * first decrementing to zero, and then removing. putIfAbsent or replace could observe the
   * intermediate zero-state. Ways we could deal with this are:
   *
   * - Don't define any of the ConcurrentMap operations. This is the current state of affairs.
   *
   * - Define putIfAbsent and replace as treating zero and absent identically (as currently
   *   implemented below). This is a bit surprising with putIfAbsent, which really becomes

     * When a custom {@code org.apache.maven.api.spi.ModelParser} is used,
     * the path may point to a non XML file.
     * <p>
     * The POM path is also used to define the {@linkplain #getBasedir() base directory}
     * of the project.
     *
     * @return the path of the pom
     * @see #getBasedir()
     */
    @Nonnull
    Path getPomPath();

    /**

    return requireNonNull(predecessor);
  }

  private int[] requireSuccessors() {
    return requireNonNull(successor);
  }

  /*
   * We don't define getPredecessor+getSuccessor and setPredecessor+setSuccessor here because
   * they're defined above -- including logic to add and subtract 1 to map between the values stored
   * in the predecessor/successor arrays and the indexes in the elements array that they identify.
   */