assertEmpty(multimap());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEYS})
  public void testRemoveAllNullKeyPresent() {
    initMultimapWithNullKey();

    assertContentsAnyOrder(multimap().removeAll(null), getValueForNullKey());

    expectMissing(mapEntry((K) null, getValueForNullKey()));
  }