input.put("foo", 1);
    ImmutableListMultimap<String, Integer> multimap = ImmutableListMultimap.copyOf(input);
    new EqualsTester().addEqualityGroup(input, multimap).testEquals();
  }

  public void testCopyOfEmpty() {
    ArrayListMultimap<String, Integer> input = ArrayListMultimap.create();
    ImmutableListMultimap<String, Integer> multimap = ImmutableListMultimap.copyOf(input);

    input.put("foo", 3);
    input.put("foo", 1);
    ImmutableSetMultimap<Object, Object> copy = ImmutableSetMultimap.copyOf(input);
    assertEquals(3, copy.size());
  }

  public void testCopyOfEmpty() {
    HashMultimap<String, Integer> input = HashMultimap.create();
    Multimap<String, Integer> multimap = ImmutableSetMultimap.copyOf(input);
    assertEquals(multimap, input);
    assertEquals(input, multimap);

    input.put("foo", 3);
    input.put("foo", 1);
    ImmutableSetMultimap<Object, Object> copy = ImmutableSetMultimap.copyOf(input);
    assertEquals(3, copy.size());
  }

  public void testCopyOfEmpty() {
    HashMultimap<String, Integer> input = HashMultimap.create();
    Multimap<String, Integer> multimap = ImmutableSetMultimap.copyOf(input);
    assertEquals(multimap, input);
    assertEquals(input, multimap);