assertThrows(IllegalArgumentException.class, () -> parse("softValues, weakValues"));

    assertThrows(IllegalArgumentException.class, () -> parse("weakValues, softValues"));

    assertThrows(IllegalArgumentException.class, () -> parse("weakValues, weakValues"));
  }

  public void testParse_writeExpirationDays() {
    CacheBuilderSpec spec = parse("expireAfterWrite=10d");

    return ImmutableList.of(createMapMaker().weakKeys(), createMapMaker().weakKeys().weakValues());
  }

  private static Iterable<MapMaker> allWeakValueStrengthMakers() {
    return ImmutableList.of(
        createMapMaker().weakValues(), createMapMaker().weakKeys().weakValues());
  }

  public void testNullParameters() throws Exception {
    NullPointerTester tester = new NullPointerTester();

    return ImmutableList.of(createMapMaker().weakKeys(), createMapMaker().weakKeys().weakValues());
  }

  private static Iterable<MapMaker> allWeakValueStrengthMakers() {
    return ImmutableList.of(
        createMapMaker().weakValues(), createMapMaker().weakKeys().weakValues());
  }

  public void testNullParameters() throws Exception {
    NullPointerTester tester = new NullPointerTester();

 * expireAfterWrite}, {@link #expireAfterAccess expireAfterAccess}, {@link #weakKeys weakKeys},
 * {@link #weakValues weakValues}, or {@link #softValues softValues} are requested.
 *
 * <p>If {@link #maximumSize(long) maximumSize} or {@link #maximumWeight(long) maximumWeight} is
 * requested entries may be evicted on each cache modification.
 *

    assertThrows(IllegalStateException.class, () -> builder1.weakKeys());
  }

  @GwtIncompatible // weakValues
  public void testValueStrengthSetTwice() {
    CacheBuilder<Object, Object> builder1 = CacheBuilder.newBuilder().weakValues();
    assertThrows(IllegalStateException.class, () -> builder1.weakValues());
    assertThrows(IllegalStateException.class, () -> builder1.softValues());

 * expireAfterWrite}, {@link #expireAfterAccess expireAfterAccess}, {@link #weakKeys weakKeys},
 * {@link #weakValues weakValues}, or {@link #softValues softValues} are requested.
 *
 * <p>If {@link #maximumSize(long) maximumSize} or {@link #maximumWeight(long) maximumWeight} is
 * requested entries may be evicted on each cache modification.
 *

            } else {
              return "0";
            }
          }
        };

    LoadingCache<Integer, String> recursiveCache =
        CacheBuilder.newBuilder().weakKeys().weakValues().build(recursiveLoader);
    cacheRef.set(recursiveCache);
    assertThat(recursiveCache.getUnchecked(3)).isEqualTo("3, 2, 1, 0");

    recursiveLoader =
        new CacheLoader<Integer, String>() {

            .createTestSuite());
    suite.addTest(
        ConcurrentMapTestSuiteBuilder.using(
                new TestStringCacheGenerator(createCacheBuilder().weakValues()))
            .named("LocalCache with weakValues") // values are string literals and won't be GC'd
            .withFeatures(
                CollectionSize.ANY,
                MapFeature.GENERAL_PURPOSE,

            .createTestSuite());
    suite.addTest(
        ConcurrentMapTestSuiteBuilder.using(
                new TestStringCacheGenerator(createCacheBuilder().weakValues()))
            .named("LocalCache with weakValues") // values are string literals and won't be GC'd
            .withFeatures(
                CollectionSize.ANY,
                MapFeature.GENERAL_PURPOSE,

    CountingLoader countingLoader = new CountingLoader();
    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder().weakValues().build(countingLoader);
    ConcurrentMap<Object, Object> map = cache.asMap();

    int iterations = 10;
    WeakReference<Object> ref = new WeakReference<>(null);
    int expectedComputations = 0;