verifySetContents(set, EMPTY_COLLECTION);
  }

  public void testNewTreeSetEmpty() {
    TreeSet<Integer> set = Sets.newTreeSet();
    verifySortedSetContents(set, EMPTY_COLLECTION, null);
  }

  public void testNewTreeSetEmptyDerived() {
    TreeSet<Derived> set = Sets.newTreeSet();
    assertTrue(set.isEmpty());
    set.add(new Derived("foo"));
    set.add(new Derived("bar"));

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.NavigableSet;
import java.util.TreeSet;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests operations on a NavigableSet. Can't be invoked directly; please
 * see {@code NavigableSetTestSuiteBuilder}.
 *
 * @author Jesse Wilson

  }

  private static class SortedSetSupplier extends CountingSupplier<TreeSet<Integer>> {
    @Override
    public TreeSet<Integer> getImpl() {
      return Sets.newTreeSet(INT_COMPARATOR);
    }

    private static final long serialVersionUID = 0;
  }

  public void testNewSortedSetMultimap() {
    CountingSupplier<TreeSet<Integer>> factory = new SortedSetSupplier();

    return asList(elements).iterator();
  }

  // In GWT, java.util.TreeSet throws ClassCastException when the comparator
  // throws it, unlike JDK6.  Therefore, we accept ClassCastException as a
  // valid result thrown by java.util.TreeSet#equals.
  private static void assertNotEqualLenient(TreeSet<?> unexpected, SortedSet<?> actual) {
    try {
      assertThat(actual).isNotEqualTo(unexpected);

  private static <E extends Comparable<? super E>> SortedSet<E> nullCheckedTreeSet(E[] elements) {
    SortedSet<E> set = newTreeSet();
    for (E element : elements) {
      // Explicit null check because TreeSet wrongly accepts add(null) when empty.
      set.add(checkNotNull(element));
    }
    return set;
  }

  public static class ContiguousSetGenerator extends AbstractContiguousSetGenerator {
    @Override

  public SafeTreeSet() {
    this(new TreeSet<E>());
  }

  public SafeTreeSet(Collection<? extends E> collection) {
    this(new TreeSet<E>(collection));
  }

  public SafeTreeSet(Comparator<? super E> comparator) {
    this(new TreeSet<E>(comparator));
  }

  public SafeTreeSet(SortedSet<E> set) {
    this(new TreeSet<E>(set));
  }

  private SafeTreeSet(NavigableSet<E> delegate) {

    MultisetTestSuiteBuilder.NoRecurse.NO_ENTRY_SET, // Cannot create entries with count > 1
  };

  static final Supplier<TreeSet<String>> STRING_TREESET_FACTORY =
      new Supplier<TreeSet<String>>() {
        @Override
        public TreeSet<String> get() {
          return new TreeSet<>(Ordering.natural().nullsLast());
        }
      };

import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.NavigableSet;
import java.util.SortedSet;
import java.util.TreeSet;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link Sets#synchronizedNavigableSet(NavigableSet)}.
 *

        }
      };
    }

    /** Uses a naturally-ordered {@link TreeSet} to store value collections. */
    @SuppressWarnings("rawtypes")
    public SortedSetMultimapBuilder<K0, Comparable> treeSetValues() {
      return treeSetValues(Ordering.natural());
    }

    /**
     * Uses a {@link TreeSet} ordered by the specified comparator to store value collections.
     *

import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.NavigableSet;
import java.util.SortedSet;
import java.util.TreeSet;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Tests for {@link Sets#synchronizedNavigableSet(NavigableSet)}.
 *