@ElementTypesAreNonnullByDefault
public abstract class AbstractBiMapTester<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMapTester<K, V> {

  @Override
  protected BiMap<K, V> getMap() {
    return (BiMap<K, V>) super.getMap();
  }

  static <K extends @Nullable Object, V extends @Nullable Object> Entry<V, K> reverseEntry(
      Entry<K, V> entry) {
    return Helpers.mapEntry(entry.getValue(), entry.getKey());
  }

  private Entry<K, V> a;
  private Entry<K, V> b;
  private Entry<K, V> c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    navigableMap = (NavigableMap<K, V>) getMap();
    entries =
        Helpers.copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));

  private SortedMap<K, V> navigableMap;
  private Entry<K, V> a;
  private Entry<K, V> c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    navigableMap = (SortedMap<K, V>) getMap();
    List<Entry<K, V>> entries =
        Helpers.copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));