}

  public void testPresentInstances_callingIteratorTwice() {
    List<Optional<String>> optionals =
        ImmutableList.of(Optional.of("a"), Optional.<String>absent(), Optional.of("c"));
    Iterable<String> onlyPresent = Optional.presentInstances(optionals);
    assertThat(onlyPresent).containsExactly("a", "c").inOrder();
    assertThat(onlyPresent).containsExactly("a", "c").inOrder();
  }

   * writeLines(lines, System.getProperty("line.separator"))}.
   *
   * @throws IOException if an I/O error occurs while writing to this sink
   */
  public void writeLines(Iterable<? extends CharSequence> lines) throws IOException {
    writeLines(lines, System.getProperty("line.separator"));
  }

  /**

 * implementation for the {@link #put} and {@link #getIfPresent} methods. {@link #getAllPresent} is
 * implemented in terms of {@link #getIfPresent}; {@link #putAll} is implemented in terms of {@link
 * #put}, {@link #invalidateAll(Iterable)} is implemented in terms of {@link #invalidate}. The
 * method {@link #cleanUp} is a no-op. All other methods throw an {@link
 * UnsupportedOperationException}.
 *
 * @author Charles Fry
 * @since 10.0
 */

import com.google.common.collect.ListMultimap;
import com.google.common.collect.testing.features.MapFeature;
import java.util.List;
import org.junit.Ignore;

/**
 * Testers for {@link ListMultimap#putAll(Object, Iterable)}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")

import java.util.Set;
import org.jspecify.annotations.NullUnmarked;

@NullUnmarked
public final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
  @Override
  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
    return newHashSet(contents);
  }

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

 * always very useful information.
 *
 * <p>On the other hand, a <i>parameter</i> type of {@link ImmutableList} is generally a nuisance to
 * callers. Instead, accept {@link Iterable} and have your method or constructor body pass it to the
 * appropriate {@code copyOf} method itself.
 *
 * <p>Expressing the immutability guarantee directly in the type that user code references is a

    Integer nullInt = (Integer) null;
    Ordering<@Nullable Iterable<@Nullable Integer>> example =
        Ordering.<Integer>natural()
            .<Integer>nullsFirst()
            .<@Nullable Integer>reverse()
            .<@Nullable Integer>lexicographical()
            .reverse()
            .<Iterable<@Nullable Integer>>nullsLast();
    List<@Nullable Integer> list1 = new ArrayList<>();

    Integer nullInt = (Integer) null;
    Ordering<@Nullable Iterable<@Nullable Integer>> example =
        Ordering.<Integer>natural()
            .<Integer>nullsFirst()
            .<@Nullable Integer>reverse()
            .<@Nullable Integer>lexicographical()
            .reverse()
            .<Iterable<@Nullable Integer>>nullsLast();
    List<@Nullable Integer> list1 = new ArrayList<>();

  K[] createKeyArray(int length);

  V[] createValueArray(int length);

  SampleElements<K> sampleKeys();

  SampleElements<V> sampleValues();

  Collection<V> createCollection(Iterable<? extends V> values);

  K[] createKeyArray(int length);

  V[] createValueArray(int length);

  SampleElements<K> sampleKeys();

  SampleElements<V> sampleValues();

  Collection<V> createCollection(Iterable<? extends V> values);