assertThat(RANGE_SET_ONE.union(RANGE_SET_TWO)).isEqualTo(expected);
  }

  public void testIntersection() {
    RangeSet<Integer> expected =
        ImmutableRangeSet.<Integer>builder()
            .add(Range.closed(2, 3))
            .add(Range.open(6, 7))
            .add(Range.singleton(8))
            .build();

    assertThat(RANGE_SET_ONE.intersection(RANGE_SET_TWO)).isEqualTo(expected);
  }

   * the edge connecting the two nodes.
   */
  @CanIgnoreReturnValue
  @CheckForNull
  V removeSuccessor(N node);

  /**
   * Add {@code node} as a predecessor to the origin node. In the case of an undirected graph, it
   * also becomes a successor. Associates {@code value} with the edge connecting the two nodes.
   */
  void addPredecessor(N node, V value);

  /**

  /**
   * Compares two objects using a comparator, <i>if</i> the result of this comparison chain has not
   * already been determined.
   */
  public abstract <T extends @Nullable Object> ComparisonChain compare(
      @ParametricNullness T left, @ParametricNullness T right, Comparator<T> comparator);

  /**

   * equal to the element that preceded it, according to the specified comparator. Note that this is
   * always true when the iterable has fewer than two elements.
   */
  public static <T extends @Nullable Object> boolean isInOrder(
      Iterable<? extends T> iterable, Comparator<T> comparator) {
    checkNotNull(comparator);
    Iterator<? extends T> it = iterable.iterator();

  }

  private static final int EVEN_POWERS_OF_TWO = 0x55555555;
  private static final int ODD_POWERS_OF_TWO = 0xaaaaaaaa;

  @VisibleForTesting
  static boolean isEvenLevel(int index) {
    int oneBased = ~~(index + 1); // for GWT
    checkState(oneBased > 0, "negative index");
    return (oneBased & EVEN_POWERS_OF_TWO) > (oneBased & ODD_POWERS_OF_TWO);
  }

  /**

    assertEquals(s2, three.next().target);
    assertEquals(o1, three.next().target);
    assertFalse(three.hasNext());

    Iterator<Subscriber> two = registry.getSubscribers("");
    assertEquals(s1, two.next().target);
    assertEquals(o1, two.next().target);
    assertFalse(two.hasNext());
  }

  public static class StringSubscriber {

    @Subscribe
    public void handle(String s) {}
  }

    Object one = new Object();
    Object two = new Object();
    Object three = new Object();
    Object four = new Object();
    Object five = new Object();
    Object six = new Object();

    map.put(one, two);
    map.remove(one);
    assertNotified(listener, one, two, RemovalCause.EXPLICIT);

    map.put(two, three);
    map.remove(two, three);

    Object one = new Object();
    Object two = new Object();
    Object three = new Object();
    Object four = new Object();
    Object five = new Object();
    Object six = new Object();

    map.put(one, two);
    map.remove(one);
    assertNotified(listener, one, two, RemovalCause.EXPLICIT);

    map.put(two, three);
    map.remove(two, three);

import java.util.Map.Entry;
import junit.framework.TestCase;

/**
 * Tests for {@code AbstractBiMap}.
 *
 * @author Mike Bostock
 */
public class AbstractBiMapTest extends TestCase {

  // The next two tests verify that map entries are not accessed after they're
  // removed, since IdentityHashMap throws an exception when that occurs.
  @SuppressWarnings("IdentityHashMapBoxing") // explicitly testing IdentityHashMap

  @VisibleForTesting static final long MAX_SIGNED_POWER_OF_TWO = 1L << (Long.SIZE - 2);

  /**
   * Returns the smallest power of two greater than or equal to {@code x}. This is equivalent to
   * {@code checkedPow(2, log2(x, CEILING))}.
   *
   * @throws IllegalArgumentException if {@code x <= 0}
   * @throws ArithmeticException of the next-higher power of two is not representable as a {@code
   *     long}, i.e. when {@code x > 2^62}