import java.util.Collections;
import java.util.Iterator;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A utility for testing an Iterator implementation by comparing its behavior to that of a "known
 * good" reference implementation. In order to accomplish this, it's important to test a great
 * variety of sequences of the {@link Iterator#next}, {@link Iterator#hasNext} and {@link

    return (MinimalIterable) of(elements.toArray());
  }

  private @Nullable Iterator<E> iterator;

  private MinimalIterable(Iterator<E> iterator) {
    this.iterator = iterator;
  }

  @Override
  public Iterator<E> iterator() {
    if (iterator == null) {
      // TODO: throw something else? Do we worry that people's code and tests

    }
  }

  /**
   * Verifies that an Iterator is unmodifiable.
   *
   * <p>This test only works with iterators that iterate over a finite set.
   */
  public static void assertIteratorIsUnmodifiable(Iterator<?> iterator) {
    while (iterator.hasNext()) {
      iterator.next();
      try {
        iterator.remove();
        fail("Remove on unmodifiable iterator succeeded");

      @Override
      public Iterator<T> iterator() {
        if (iterable instanceof List) {
          List<T> list = (List<T>) iterable;
          int toSkip = Math.min(list.size(), numberToSkip);
          return list.subList(toSkip, list.size()).iterator();
        }
        Iterator<T> iterator = iterable.iterator();

        Iterators.advance(iterator, numberToSkip);

        /*

     */
    public MultiIterator(final Iterator<E>... iterators) {
        assertArgumentNotNull("iterators", iterators);
        this.iterators = iterators;
    }

    @Override
    public boolean hasNext() {
        for (; index < iterators.length; ++index) {
            if (iterators[index].hasNext()) {
                return true;
            }
        }

        TestIterator iterator = new TestIterator(null);

        // Verify iteration
        assertTrue(iterator.hasNext());
        assertSame(resource, iterator.next());

        assertTrue(iterator.hasNext());
        assertSame(resource, iterator.next());

        assertTrue(iterator.hasNext());
        assertSame(resource, iterator.next());

        assertFalse(iterator.hasNext());

  public void testEntrySet_iteratorRemovePropagates() {
    Iterator<Multiset.Entry<E>> iterator = getMultiset().entrySet().iterator();
    assertTrue(
        "non-empty multiset.entrySet() iterator.hasNext() returned false", iterator.hasNext());
    assertEquals(
        "multiset.entrySet() iterator.next() returned incorrect entry",
        Multisets.immutableEntry(e0(), 1),
        iterator.next());
    assertFalse(

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Iterator;
import org.jspecify.annotations.Nullable;

/**
 * An iterator which forwards all its method calls to another iterator. Subclasses should override
 * one or more methods to modify the behavior of the backing iterator as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *

    } else if (isEmpty()) {
      return true;
    }

    if (SortedIterables.hasSameComparator(comparator, that)) {
      Iterator<?> otherIterator = that.iterator();
      try {
        Iterator<E> iterator = iterator();
        while (iterator.hasNext()) {
          Object element = iterator.next();
          Object otherElement = otherIterator.next();

 * ordinarily difficult to write iterators for. But using this class, one must implement only the
 * {@link #computeNext} method, and invoke the {@link #endOfData} method when appropriate.
 *
 * <p>Another example is an iterator that skips over null elements in a backing iterator. This could
 * be implemented as:
 *
 * {@snippet :
 * public static Iterator<String> skipNulls(final Iterator<String> in) {