Multimap<String, Integer> multimap = ImmutableSetMultimap.copyOf(input);
    assertEquals(multimap, input);
    assertEquals(input, multimap);
  }

  public void testCopyOfImmutableSetMultimap() {
    Multimap<String, Integer> multimap = createMultimap();
    assertSame(multimap, ImmutableSetMultimap.copyOf(multimap));
  }

  public void testCopyOfNullKey() {