@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MultisetAddTester<E> extends AbstractMultisetTester<E> {
  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  public void testAddUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> getMultiset().add(e0()));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddMeansAddOne() {