}
    }
    return builder.append("]").toString();
  }

  /**
   * Provide a human-readable explanation of why this future has not yet completed.
   *
   * @return null if an explanation cannot be provided because the future is done.
   */
  @Nullable
  String pendingToString() {
    if (state == State.DELEGATED) {
      return "setFuture=[" + delegate + "]";
    }
    return null;
  }

 * iteratorTester.testForEachRemaining();
 * }</pre>
 *
 * <p><b>Note</b>: It is necessary to use {@code IteratorTester.KnownOrder} as shown above, rather
 * than {@code KnownOrder} directly, because otherwise the code cannot be compiled.
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class IteratorTester<E extends @Nullable Object>

 * #minValue} and {@link #maxValue} should also be overridden for bounded types.
 *
 * <p>A discrete domain always represents the <i>entire</i> set of values of its type; it cannot
 * represent partial domains such as "prime integers" or "strings of length 5."
 *
 * <p>See the Guava User Guide section on <a href=
 * "https://github.com/google/guava/wiki/RangesExplained#discrete-domains">{@code

        if (emptyInstanceGenerated.get(type.getType()).intValue() == freshness.get()) {
          // same freshness, generate again.
          return invokeGeneratorMethod(emptyGenerate);
        } else {
          // Cannot use empty generator. Proceed with other generators.
        }
      } else {
        // never generated empty instance for this type before.
        Object emptyInstance = invokeGeneratorMethod(emptyGenerate);

      case CEILING:
        return Integer.SIZE - Integer.numberOfLeadingZeros(x - 1);

      case HALF_DOWN:
      case HALF_UP:
      case HALF_EVEN:
        // Since sqrt(2) is irrational, log2(x) - logFloor cannot be exactly 0.5
        int leadingZeros = Integer.numberOfLeadingZeros(x);
        int cmp = MAX_POWER_OF_SQRT2_UNSIGNED >>> leadingZeros;
        // floor(2^(logFloor + 0.5))

import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A series of tests that support asserting that collections cannot be modified, either through
 * direct or indirect means.
 *
 * @author Robert Konigsberg
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class UnmodifiableCollectionTests {

  private final Map<N, Object> adjacentNodeValues;

  /**
   * All node connections in this graph, in edge insertion order.
   *
   * <p>Note: This field and {@link #adjacentNodeValues} cannot be combined into a single
   * LinkedHashMap because one target node may be mapped to both a predecessor and a successor. A
   * LinkedHashMap combines two such edges into a single node-value pair, even though the edges may

    public boolean equals(@CheckForNull Object object) {
      // Cannot use key and value equivalence
      if (object instanceof Entry) {
        Entry<?, ?> that = (Entry<?, ?>) object;
        return key.equals(that.getKey()) && value.equals(that.getValue());
      }
      return false;
    }

    @Override
    public int hashCode() {
      // Cannot use key and value equivalence

        return data.toArray();
      }
    };
  }

  /**
   * Returns a "nefarious" map entry with the specified key and value, meaning an entry that is
   * suitable for testing that map entries cannot be modified via a nefarious implementation of
   * equals. This is used for testing unmodifiable collections of map entries; for example, it

   * endpoints are unordered and the graph is directed; it simply returns {@code false}. This is for
   * consistency with the behavior of {@link Collection#contains(Object)} (which does not generally
   * throw if the object cannot be present in the collection), and the desire to have this method's
   * behavior be compatible with {@code edges().contains(endpoints)}.
   *
   * @since 27.1
   */
  @Override