*
 * <p>The edge is a self-loop if, and only if, the two endpoints are equal.
 *
 * @author James Sexton
 * @since 20.0
 */
@Beta
@Immutable(containerOf = {"N"})
public abstract class EndpointPair<N> implements Iterable<N> {
  private final N nodeU;
  private final N nodeV;

  private EndpointPair(N nodeU, N nodeV) {
    this.nodeU = checkNotNull(nodeU);
    this.nodeV = checkNotNull(nodeV);
  }

 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public class ComparatorsTest extends TestCase {
  public void testLexicographical() {
    Comparator<String> comparator = Ordering.natural();
    Comparator<Iterable<String>> lexy = Comparators.lexicographical(comparator);

    ImmutableList<String> empty = ImmutableList.of();
    ImmutableList<String> a = ImmutableList.of("a");
    ImmutableList<String> aa = ImmutableList.of("a", "a");

  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAll_nullCollectionReference() {
    assertThrows(NullPointerException.class, () -> getMap().putAll(null));
  }

  private void putAll(Iterable<Entry<K, V>> entries) {
    Map<K, V> map = new LinkedHashMap<>();
    for (Entry<K, V> entry : entries) {
      map.put(entry.getKey(), entry.getValue());
    }
    getMap().putAll(map);
  }

  /**

      return arithmetic.toString();
    }
  }

  private interface ParameterTypesDifferent {
    void foo(
        String s,
        Runnable r,
        Number n,
        Iterable<?> it,
        boolean b,
        Equivalence<String> eq,
        Exception e,
        InputStream in,
        Comparable<?> c,
        Ordering<Integer> ord,
        Charset charset,

  }

  public void testSize() {
    assertEquals(1, testTable.size());
  }

  public void testValues() {
    assertThat(testTable.values()).contains("blah");
  }

  @Override
  Iterable<ImmutableTable<Character, Integer, String>> getTestInstances() {
    return ImmutableSet.of(testTable);
  }

   * throws a {@link NullPointerException}.
   *
   * <p>To find the first non-null element in an iterable, use {@code Iterables.find(iterable,
   * Predicates.notNull())}. For varargs, use {@code Iterables.find(Arrays.asList(a, b, c, ...),
   * Predicates.notNull())}, static importing as necessary.
   *

  /** Most of the tests in this class run against every one of these caches. */
  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Object, Object>>() {

  }

  // TODO(cpovirk): should we reject null items, since the tests already check null automatically?
  @CanIgnoreReturnValue
  public RelationshipTester<T> addRelatedGroup(Iterable<? extends T> group) {
    groups.add(ImmutableList.copyOf(group));
    return this;
  }

  public void test() {
    for (int groupNumber = 0; groupNumber < groups.size(); groupNumber++) {

  }

  @SafeVarargs
  @CanIgnoreReturnValue
  public final Ordered expect(Object... elements) {
    return expect(asList(elements));
  }

  @CanIgnoreReturnValue
  public final Ordered expect(Iterable<?> elements) {
    List<List<E>> resultsForAllStrategies = new ArrayList<>();
    for (Supplier<GeneralSpliterator<E>> spliteratorSupplier : spliteratorSuppliers) {

  }

  @SafeVarargs
  @CanIgnoreReturnValue
  public final Ordered expect(Object... elements) {
    return expect(asList(elements));
  }

  @CanIgnoreReturnValue
  public final Ordered expect(Iterable<?> elements) {
    List<List<E>> resultsForAllStrategies = new ArrayList<>();
    for (Supplier<GeneralSpliterator<E>> spliteratorSupplier : spliteratorSuppliers) {