static final CharSink BROKEN_OPEN_SINK = new TestCharSink(OPEN_THROWS);

  private static final ImmutableSet<CharSource> BROKEN_SOURCES =
      ImmutableSet.of(BROKEN_CLOSE_SOURCE, BROKEN_OPEN_SOURCE, BROKEN_READ_SOURCE);
  private static final ImmutableSet<CharSink> BROKEN_SINKS =
      ImmutableSet.of(BROKEN_CLOSE_SINK, BROKEN_OPEN_SINK, BROKEN_WRITE_SINK);

  public void testCopyExceptions() {

    }

    // Now we check for known false positives using a set of known false positives.
    // (These are all of the false positives under 900.)
    ImmutableSet<Integer> falsePositives =
        ImmutableSet.of(
            49, 51, 59, 163, 199, 321, 325, 363, 367, 469, 545, 561, 727, 769, 773, 781);
    for (int i = 1; i < 900; i += 2) {
      if (!falsePositives.contains(i)) {

  }

  public void testGet_collections() {
    assertEquals(ImmutableSet.of().iterator(), ArbitraryInstances.get(Iterator.class));
    assertFalse(ArbitraryInstances.get(PeekingIterator.class).hasNext());
    assertFalse(ArbitraryInstances.get(ListIterator.class).hasNext());
    assertEquals(ImmutableSet.of(), ArbitraryInstances.get(Iterable.class));
    assertEquals(ImmutableSet.of(), ArbitraryInstances.get(Set.class));

      assertSame(thrownException, expected);
    }

    assertTrue(c1.isClosed());
    assertTrue(c2.isClosed());

    ImmutableSet<Throwable> suppressed = ImmutableSet.copyOf(thrownException.getSuppressed());
    assertEquals(2, suppressed.size());

    assertEquals(ImmutableSet.of(c1Exception, c2Exception), suppressed);
  }

  public void testNullCloseable() throws IOException {
    Closer closer = Closer.create();

    Set<Object> original = ImmutableSet.of(new Object(), new Object());

    assertThrows(ClassCastException.class, () -> ImmutableSortedSet.copyOf(original));
  }

  public void testImmutableSortedSetCopyOfIterator() {
    // false positive: `new Object()` is not equal to `new Object()`
    @SuppressWarnings("DistinctVarargsChecker")
    Set<Object> original = ImmutableSet.of(new Object(), new Object());

    Set<Object> original = ImmutableSet.of(new Object(), new Object());

    assertThrows(ClassCastException.class, () -> ImmutableSortedSet.copyOf(original));
  }

  public void testImmutableSortedSetCopyOfIterator() {
    // false positive: `new Object()` is not equal to `new Object()`
    @SuppressWarnings("DistinctVarargsChecker")
    Set<Object> original = ImmutableSet.of(new Object(), new Object());

    assertFalse(isOneOrFive.apply(null));
  }

  public void testIn_equality() {
    Collection<Integer> nums = ImmutableSet.of(1, 5);
    Collection<Integer> sameOrder = ImmutableSet.of(1, 5);
    Collection<Integer> differentOrder = ImmutableSet.of(5, 1);
    Collection<Integer> differentNums = ImmutableSet.of(1, 3, 5);

    new EqualsTester()
        .addEqualityGroup(
            Predicates.in(nums),

    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");
  }

  private static final ImmutableSet<Integer> CHUNK_SIZES =
      ImmutableSet.of(1, 2, 3, Integer.MAX_VALUE);

  private static void bufferHelper(String input, String... expect) throws IOException {

    List<String> expectProcess = Arrays.asList(expect);

    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");
  }

  private static final ImmutableSet<Integer> CHUNK_SIZES =
      ImmutableSet.of(1, 2, 3, Integer.MAX_VALUE);

  private static void bufferHelper(String input, String... expect) throws IOException {

    List<String> expectProcess = Arrays.asList(expect);

import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@link ImmutableSet} with exactly one element.
 *
 * @author Kevin Bourrillion
 * @author Nick Kralevich
 */
@GwtCompatible
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
final class SingletonImmutableSet<E> extends ImmutableSet<E> {
  // We deliberately avoid caching the asList and hashCode here, to ensure that with