ALLOWS_NULL_KEYS);
  }

  /**
   * Map generator that verifies that {@code setUp()} methods are called in all the test cases. The
   * {@code setUpRan} parameter is set true by the {@code setUp} that every test case is supposed to
   * have registered, and set false by the {@code tearDown}. We use a dynamic proxy to intercept all
   * of the {@code Map} method calls and check that {@code setUpRan} is true.
   */

    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");
    // These have a combination of invalid length, unrecognized characters and wrong padding.

         *
         * We carry out this computation in modular arithmetic. Since times2ToThe32Mod accepts any
         * unsigned long, we don't have to do a mod on every operation, only when intermediate
         * results can exceed 2^63.
         */
        long result = times2ToThe32Mod(aHi * bHi /* < 2^62 */, m); // < m < 2^63

    }

    // Test #entries()
    assertCollectionIsUnmodifiable(multimap.entries(), Maps.immutableEntry(sampleKey, sampleValue));
    assertMultimapRemainsUnmodified(multimap, originalEntries);

    // Iterate over every element in the entry set
    for (Entry<K, V> entry : multimap.entries()) {
      assertMapEntryIsUnmodifiable(entry);
    }
    assertMultimapRemainsUnmodified(multimap, originalEntries);

    // Test #keys()

 * <p>A "lock-like object" is really any object that may be used for concurrency control. If the
 * {@link #callAndAssertBlocks} method is ever called in a test, the lock-like object must have a
 * method equivalent to {@link java.util.concurrent.locks.ReentrantLock#hasQueuedThread(Thread)}. If
 * the {@link #callAndAssertWaits} method is ever called in a test, the lock-like object must have a
 * method equivalent to {@link

import java.util.function.ToIntFunction;
import java.util.stream.Collector;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link Multiset} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Grouped iteration.</b> In all current implementations, duplicate elements always appear

   * Future} fails with the given {@code exceptionType}, from the result provided by the {@code
   * fallback}. {@link Function#apply} is not invoked until the primary input has failed, so if the
   * primary input succeeds, it is never invoked. If, during the invocation of {@code fallback}, an
   * exception is thrown, this exception is used as the result of the output {@code Future}.
   *
   * <p>Usage example:
   *
   * <pre>{@code

    private final int size;

    ImmutableArrayMap(int size) {
      this.size = size;
    }

    abstract ImmutableMap<K, Integer> keyToIndex();

    // True if getValue never returns null.
    private boolean isFull() {
      return size == keyToIndex().size();
    }

    K getKey(int index) {
      return keyToIndex().keySet().asList().get(index);
    }

    @CheckForNull

import java.util.stream.Collector;
import java.util.stream.Stream;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link SetMultimap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Warning:</b> As in all {@link SetMultimap}s, do not modify either a key <i>or a value</i>

   * the underlying collection.
   *
   * <p>The returned collection isn't threadsafe or serializable, even if {@code unfiltered} is.
   *
   * <p>Many of the filtered collection's methods, such as {@code size()}, iterate across every
   * element in the underlying collection and determine which elements satisfy the filter. When a
   * live view is <i>not</i> needed, it may be faster to copy {@code Iterables.filter(unfiltered,
   * predicate)} and use the copy.