}

  public void testCopyOf_map_empty() {
    Map<Class<?>, Object> in = Collections.emptyMap();
    ClassToInstanceMap<Object> map = ImmutableClassToInstanceMap.copyOf(in);
    assertTrue(map.isEmpty());
    assertSame(map, ImmutableClassToInstanceMap.of());
    assertSame(map, ImmutableClassToInstanceMap.copyOf(map));
  }

  public void testOf_zero() {

   */
  public static <K, V> ImmutableMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    if ((map instanceof ImmutableMap) && !(map instanceof SortedMap)) {
      @SuppressWarnings("unchecked") // safe since map is not writable
      ImmutableMap<K, V> kvMap = (ImmutableMap<K, V>) map;
      if (!kvMap.isPartialView()) {
        return kvMap;
      }

  }

  public void testTransformSingletonMapEquality() {
    Map<String, String> map =
        Maps.transformValues(ImmutableMap.of("a", 1), Functions.toStringFunction());
    Map<String, String> expected = ImmutableMap.of("a", "1");
    assertMapsEqual(expected, map);
    assertEquals(expected.get("a"), map.get("a"));
  }

  public void testTransformIdentityFunctionEquality() {

    assertSame(three, map.get(one));
    assertFalse(map.replace(one, two, three));
    assertSame(three, map.get(one));
    assertTrue(map.replace(one, three, two));
    assertSame(two, map.get(one));
    assertEquals(3, map.size());

    map.clear();
    assertTrue(map.isEmpty());
    assertEquals(0, map.size());

    cache.getUnchecked(one);
    assertEquals(1, map.size());
    assertSame(one, map.get(one));

        .addEqualityGroup(Functions.forMap(map))
        .addEqualityGroup(Functions.forMap(map, null))
        .addEqualityGroup(Functions.forMap(map, 43))
        .testEquals();
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testForMapWithDefault_includeSerializable() {
    Map<String, Integer> map = Maps.newHashMap();
    map.put("One", 1);
    map.put("Three", 3);

        .addEqualityGroup(Functions.forMap(map))
        .addEqualityGroup(Functions.forMap(map, null))
        .addEqualityGroup(Functions.forMap(map, 43))
        .testEquals();
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testForMapWithDefault_includeSerializable() {
    Map<String, Integer> map = Maps.newHashMap();
    map.put("One", 1);
    map.put("Three", 3);

    final Map<K, V> map;

    FunctionForMapNoDefault(Map<K, V> map) {
      this.map = checkNotNull(map);
    }

    @Override
    @ParametricNullness
    public V apply(@ParametricNullness K key) {
      V result = map.get(key);
      checkArgument(result != null || map.containsKey(key), "Key '%s' not present in map", key);
      // The unchecked cast is safe because of the containsKey check.

  }

  public void testKeySet() {
    Map<String, Integer> map = create();
    Set<String> keySet = map.keySet();
    assertTrue(keySet instanceof SynchronizedSet);
    assertSame(mutex, ((SynchronizedSet<?>) keySet).mutex);
  }

  public void testValues() {
    Map<String, Integer> map = create();
    Collection<Integer> values = map.values();
    assertTrue(values instanceof SynchronizedCollection);

  private final ImmutableMap<K, V> map;

  ImmutableMapKeySet(ImmutableMap<K, V> map) {
    this.map = map;
  }

  @Override
  public int size() {
    return map.size();
  }

  @Override
  public UnmodifiableIterator<K> iterator() {
    return map.keyIterator();
  }

  @Override
  public Spliterator<K> spliterator() {
    return map.keySpliterator();
  }

  @Override

  static final Predicate<Entry<String, Integer>> CORRECT_LENGTH =
      input -> input.getKey().length() == input.getValue();

  abstract Map<String, Integer> createUnfiltered();

  public void testFilteredKeysIllegalPut() {
    Map<String, Integer> unfiltered = createUnfiltered();
    Map<String, Integer> filtered = Maps.filterKeys(unfiltered, NOT_LENGTH_3);
    filtered.put("a", 1);
    filtered.put("b", 2);