public class SortedSetNavigationTester<E extends @Nullable Object> extends AbstractSetTester<E> {

  private SortedSet<E> sortedSet;
  private List<E> values;
  private @Nullable E a;
  private @Nullable E b;
  private @Nullable E c;

  @Override
  public void setUp() throws Exception {
    super.setUp();
    sortedSet = (SortedSet<E>) getSet();
    values =
        copyToList(
            getSubjectGenerator()

  }

  public static class Strings extends SampleElements<String> {
    public Strings() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super("b", "a", "c", "d", "e");
    }

    // for testing SortedSet and SortedMap methods
    public static final String BEFORE_FIRST = "\0";
    public static final String BEFORE_FIRST_2 = "\0\0";

  }

  public static class Strings extends SampleElements<String> {
    public Strings() {
      // elements aren't sorted, to better test SortedSet iteration ordering
      super("b", "a", "c", "d", "e");
    }

    // for testing SortedSet and SortedMap methods
    public static final String BEFORE_FIRST = "\0";
    public static final String BEFORE_FIRST_2 = "\0\0";

import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * Basic implementation of a {@link SortedSetMultimap} with a sorted key set.
 *
 * <p>This superclass allows {@code TreeMultimap} to override methods to return navigable set and
 * map types in non-GWT only, while GWT code will inherit the SortedMap/SortedSet overrides.
 *
 * @author Louis Wasserman
 */
@GwtCompatible

    implements TestSortedSetGenerator<String> {

  @Override
  public SortedSet<String> create(Object... elements) {
    return (SortedSet<String>) super.create(elements);
  }

  @Override
  protected abstract SortedSet<String> create(String[] elements);

  /** Sorts the elements by their natural ordering. */
  /*

  public void testEmpty_serialization() {
    SortedSet<String> set = new SafeTreeSet<>();
    SortedSet<String> copy = SerializableTester.reserializeAndAssert(set);
    assertEquals(set.comparator(), copy.comparator());
  }

  @GwtIncompatible // SerializableTester
  public void testSingle_serialization() {
    SortedSet<String> set = new SafeTreeSet<>();
    set.add("e");

import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import org.jspecify.annotations.Nullable;

/**
 * Basic implementation of a {@link SortedSetMultimap} with a sorted key set.
 *
 * <p>This superclass allows {@code TreeMultimap} to override methods to return navigable set and
 * map types in non-GWT only, while GWT code will inherit the SortedMap/SortedSet overrides.
 *
 * @author Louis Wasserman
 */
@GwtCompatible

    implements TestSortedSetGenerator<String> {

  @Override
  public SortedSet<String> create(Object... elements) {
    return (SortedSet<String>) super.create(elements);
  }

  @Override
  protected abstract SortedSet<String> create(String[] elements);

  /** Sorts the elements by their natural ordering. */
  /*

    Comparator<?> comparator2;
    if (elements instanceof SortedSet) {
      comparator2 = comparator((SortedSet<?>) elements);
    } else if (elements instanceof SortedIterable) {
      comparator2 = ((SortedIterable<?>) elements).comparator();
    } else {
      return false;
    }
    return comparator.equals(comparator2);
  }

  @SuppressWarnings("unchecked")
  // if sortedSet.comparator() is null, the set must be naturally ordered

  @Override
  protected abstract SortedSetMultimap<K, V> delegate();

  @Override
  public SortedSet<V> get(@ParametricNullness K key) {
    return delegate().get(key);
  }

  @Override
  public SortedSet<V> removeAll(@Nullable Object key) {
    return delegate().removeAll(key);
  }

  @Override
  public SortedSet<V> replaceValues(@ParametricNullness K key, Iterable<? extends V> values) {