});
    assertTrue(1 >= cache.size());
  }

  public void testCompute() {
    cache.put(key, "1");
    // simultaneous deletion
    doParallelCacheOp(
        count,
        n -> {
          cache.asMap().compute(key, (k, v) -> null);
        });
    assertEquals(0, cache.size());
  }

  public void testComputeWithLoad() {

  /** Constructor for use by subclasses. */
  protected Equivalence() {}

  /**
   * Returns {@code true} if the given objects are considered equivalent.
   *
   * <p>This method describes an <i>equivalence relation</i> on object references, meaning that for
   * all references {@code x}, {@code y}, and {@code z} (any of which may be null):
   *
   * <ul>
   *   <li>{@code equivalent(x, x)} is true (<i>reflexive</i> property)

{
  /** Constructor for use by subclasses. */
  protected Equivalence() {}

  /**
   * Returns {@code true} if the given objects are considered equivalent.
   *
   * <p>This method describes an <i>equivalence relation</i> on object references, meaning that for
   * all references {@code x}, {@code y}, and {@code z} (any of which may be null):
   *
   * <ul>
   *   <li>{@code equivalent(x, x)} is true (<i>reflexive</i> property)

   *
   * <p>Being reflexive, antisymmetric and transitive, the {@code encloses} relation defines a
   * <i>partial order</i> over ranges. There exists a unique {@linkplain Range#all maximal} range
   * according to this relation, and also numerous {@linkplain #isEmpty minimal} ranges. Enclosure
   * also implies {@linkplain #isConnected connectedness}.
   */

 *
 * <ul>
 *   <li>SafeAtomicHelper: uses AtomicReferenceFieldsUpdaters to implement synchronization
 *   <li>SynchronizedHelper: uses {@code synchronized} blocks for synchronization
 * </ul>
 *
 * To force selection of our fallback strategies we load {@link AbstractFuture} (and all of {@code
 * com.google.common.util.concurrent}) in degenerate class loaders which make certain platform

    @Override
    public String toStringWithRelation() { // #pending
        return toString();
    }

    @Override
    public String buildDisplayString(String name, boolean column, boolean relation) { // #pending
        return toString();
    }

    // ===================================================================================

 * probably roll its own.
 * <p>
 * This implementation is backed by Maven Resolver API, supported protocols and transport selection depends on it. If
 * resolver preference regarding transport is altered, it will affect this service as well.
 *
 * @since 4.0.0
 */
@Experimental
@Consumer
public interface TransportProvider extends Service {

   *       Double.NEGATIVE_INFINITY} are fuzzily equal only to themselves.
   * </ul>
   *
   * <p>This is reflexive and symmetric, but not transitive, so it is not an
   * equivalence relation and not suitable for use in {@link Object#equals}
   * implementations.
   *
   * @throws IllegalArgumentException if {@code tolerance} is {@code < 0} or NaN
   * @since 13.0
   */

   * given object is also a multiset and contains equal elements with equal counts, regardless of
   * order.
   */
  @Override
  // TODO(kevinb): caveats about equivalence-relation?
  boolean equals(@CheckForNull Object object);

  /**
   * Returns the hash code for this multiset. This is defined as the sum of
   *
   * <pre>{@code

      int[] allRequired, int requiredFrom, int requiredTo, double[] array, int from, int to) {
    // Choose the first selection to do...
    int requiredChosen = chooseNextSelection(allRequired, requiredFrom, requiredTo, from, to);
    int required = allRequired[requiredChosen];

    // ...do the first selection...
    selectInPlace(required, array, from, to);

    // ...then recursively perform the selections in the range below...