* swapping them.
   *
   * <p>An empty iterable has only one permutation, which is an empty list.
   *
   * @param elements the original iterable whose elements have to be permuted.
   * @param comparator a comparator for the iterable's elements.
   * @return an immutable {@link Collection} containing all the different permutations of the
   *     original iterable.

public final class IterablesFilterArrayListTest
    extends AbstractFilteredIterableTest<Iterable<Integer>> {
  @Override
  Iterable<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Lists.newArrayList(contents);
  }

  @Override
  Iterable<Integer> filter(Iterable<Integer> elements, Predicate<? super Integer> predicate) {
    return Iterables.filter(elements, predicate);
  }

   * accepts non-{@code Collection} iterables and empty iterables.
   */
  public static <E extends Enum<E>> EnumSet<E> newEnumSet(
      Iterable<E> iterable, Class<E> elementType) {
    EnumSet<E> set = EnumSet.noneOf(elementType);
    Iterables.addAll(set, iterable);
    return set;
  }

  // HashSet

  /**

import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;

  /** 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>>() {

  }

  @Override
  public Set<E> incidentEdges() {
    return new AbstractSet<E>() {
      @Override
      public UnmodifiableIterator<E> iterator() {
        Iterable<E> incidentEdges =
            (selfLoopCount == 0)
                ? Iterables.concat(inEdgeMap.keySet(), outEdgeMap.keySet())
                : Sets.union(inEdgeMap.keySet(), outEdgeMap.keySet());
        return Iterators.unmodifiableIterator(incidentEdges.iterator());

        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Key, String>>() {
          @Override

  }

  @Override
  @CanIgnoreReturnValue
  public boolean addAll(Collection<? extends E> collection) {
    int size = collection.size();
    if (size >= maxSize) {
      clear();
      return Iterables.addAll(this, Iterables.skip(collection, size - maxSize));
    }
    return standardAddAll(collection);
  }

  @Override
  @J2ktIncompatible // Incompatible return type change. Use inherited implementation

   * Returns an iterator that cycles indefinitely over the elements of {@code iterable}.
   *
   * <p>The returned iterator supports {@code remove()} if the provided iterator does. After {@code
   * remove()} is called, subsequent cycles omit the removed element, which is no longer in {@code
   * iterable}. The iterator's {@code hasNext()} method returns {@code true} until {@code iterable}
   * is empty.
   *

 * limitations under the License.
 */

package com.google.common.io;

import static com.google.common.truth.Truth.assertThat;

import com.google.common.collect.Iterables;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.File;
import java.io.IOException;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link Files#fileTraverser()}.
 *