assertThat(map.containsKey("3"), is(not(true)));
        map.put("3", null);
        assertThat(map.containsKey("3"), is(true));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testIndexOf() throws Exception {
        assertThat(map.indexOf("test"), is(1));
        assertThat(map.indexOf(null), is(0));
        assertThat(map.indexOf("test3"), is(-1));

        map.putAll(m);
        assertThat(map.get("THREE"), is("3"));
        assertThat(map.get("FOUR"), is("4"));
        assertThat(map.size(), is(4));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testPerformance() throws Exception {
        for (int j = 0; j < 3; ++j) {
            final int num = 100000;
            final Map<String, String> hmap = new HashMap<String, String>();

  }

  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 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;
      }

  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableSortedMap<K, V> copyOf(Map<? extends K, ? extends V> map) {
    return copyOfInternal((Map<K, V>) map, (Ordering<K>) Ordering.natural());
  }

  public static <K, V> ImmutableSortedMap<K, V> copyOf(
      Map<? extends K, ? extends V> map, Comparator<? super K> comparator) {
    return copyOfInternal(map, checkNotNull(comparator));
  }

    }
    if (map instanceof ImmutableSortedMap) {
      // TODO(kevinb): Prove that this cast is safe, even though
      // Collections.unmodifiableSortedMap requires the same key type.
      @SuppressWarnings("unchecked")
      ImmutableSortedMap<K, V> kvMap = (ImmutableSortedMap<K, V>) map;
      if (!kvMap.isPartialView()) {
        return kvMap;
      }
    }

    }
    if (map instanceof ImmutableSortedMap) {
      // TODO(kevinb): Prove that this cast is safe, even though
      // Collections.unmodifiableSortedMap requires the same key type.
      @SuppressWarnings("unchecked")
      ImmutableSortedMap<K, V> kvMap = (ImmutableSortedMap<K, V>) map;
      if (!kvMap.isPartialView()) {
        return kvMap;
      }
    }

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

	current     *apiPackage
	deprecated  map[token.Pos]bool
	features    map[string]bool              // set
	imported    map[string]*apiPackage       // packages already imported
	stdPackages []string                     // names, omitting "unsafe", internal, and vendored packages
	importMap   map[string]map[string]string // importer dir -> import path -> canonical path
	importDir   map[string]string            // canonical import path -> dir