}
  }

  private <T extends @Nullable Object> void actsLikeIteratorHelper(List<T> list) {
    // Check with modifiable copies of the list
    new PeekingIteratorTester<T>(list).test();

    // Check with unmodifiable lists
    new IteratorTester<T>(
        list.size() * 2 + 2, UNMODIFIABLE, list, IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<T> newTargetIterator() {

import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.testing.Helpers.mapEntry;
import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;

    }
  }

  private <T extends @Nullable Object> void actsLikeIteratorHelper(List<T> list) {
    // Check with modifiable copies of the list
    new PeekingIteratorTester<T>(list).test();

    // Check with unmodifiable lists
    new IteratorTester<T>(
        list.size() * 2 + 2, UNMODIFIABLE, list, IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<T> newTargetIterator() {

    assertUnmodifiableIterableInTandem(
        unmodifiable.asMap().entrySet(), multimap.asMap().entrySet());

    assertEquals(multimap.toString(), unmodifiable.toString());
    assertEquals(multimap.hashCode(), unmodifiable.hashCode());
    assertEquals(multimap, unmodifiable);

    assertThat(unmodifiable.asMap().get("bar")).containsExactly(5, -1);

    EmptyIteratorTester() {
      super(3, MODIFIABLE, Collections.<Integer>emptySet(), IteratorTester.KnownOrder.KNOWN_ORDER);
    }
  }

  @GwtIncompatible // Only used by @GwtIncompatible code
  private abstract static class SingletonIteratorTester extends IteratorTester<Integer> {
    SingletonIteratorTester() {
      super(3, MODIFIABLE, singleton(1), IteratorTester.KnownOrder.KNOWN_ORDER);
    }
  }

 * value and the old value.
 *
 * <p>Keys and values may be null. All optional multimap methods are supported, and all returned
 * views are modifiable.
 *
 * <p>The lists returned by {@link #get}, {@link #removeAll}, and {@link #replaceValues} all
 * implement {@link java.util.RandomAccess}.
 *

import static com.google.common.collect.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
import static com.google.common.collect.testing.IteratorFeature.UNMODIFIABLE;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;
import static java.util.Collections.emptyList;

        assertEquals(123, metaDataMap.get("key2"));
        assertEquals(true, metaDataMap.get("key3"));
    }

    public void test_metaDataMapModifiable() {
        // Test that metadata map is modifiable
        ResponseData data = new ResponseData();

        data.addMetaData("key1", "value1");

        Map<String, Object> metaDataMap = data.getMetaDataMap();
        metaDataMap.put("key2", "value2");

    CacheBuilder<Object, Object> builder = createCacheBuilder().concurrencyLevel(1);
    LocalLoadingCache<Object, Object> cache = makeCache(builder, identityLoader());
    ConcurrentMap<Object, Object> map = cache.localCache; // modifiable map view
    assertThat(cache.stats()).isEqualTo(EMPTY_STATS);

    Object one = new Object();
    assertThat(map.put(one, one)).isNull();
    assertThat(map.get(one)).isSameInstanceAs(one);

  // here to provide error messages.
  // TODO(user): Some Strings used in the subclasses can be added as static Strings
  // here too.
  static final String ERROR_MODIFIABLE_SET = "Set returned is unexpectedly modifiable";
  static final String ERROR_SELF_LOOP = "self-loops are not allowed";
  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";