assertEquals(emptySet(), multimap.keySet());
    assertEquals(0, multimap.size());
    assertTrue(multimap.values().isEmpty());
    assertEquals("{}", multimap.toString());
  }

  public void testEmptyMultimapWrites() {
    Multimap<String, Integer> multimap = ImmutableListMultimap.of();
    UnmodifiableCollectionTests.assertMultimapIsUnmodifiable(multimap, "foo", 1);
  }