expectUnchanged();
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testRemoveAll_containsNullYes() {
    initCollectionWithNullElement();
    assertTrue("removeAll(containsNull) should return true", collection.removeAll(singleton(null)));
    // TODO: make this work with MinimalCollection
  }