expectUnchanged();
    expectNullMissingWhenNullUnsupported(
        "Should not contain null after unsupported addAll(containsNull)");
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddAll_nullCollectionReference() {
    assertThrows(NullPointerException.class, () -> collection.addAll(null));
  }

  /**
   * Returns the {@link Method} instance for {@link #testAddAll_nullUnsupported()} so that tests can