/**
 * Unit test for {@link Helpers}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
public class HelpersTest extends TestCase {
  public void testNullsBeforeB() {
    testComparator(NullsBeforeB.INSTANCE, "a", "azzzzzz", null, "b", "c");
  }

  public void testIsEmpty_iterable() {
    List<Object> list = new ArrayList<>();
    assertEmpty(list);
    assertEmpty(() -> emptyIterator());

    list.add("a");

    private final List<Sitemap> sitemapList = new ArrayList<>();

    /** The type of this sitemap set (URLSET or INDEX). */
    private String type = URLSET;

    /**
     * Creates a new SitemapSet instance with default type URLSET.
     */
    public SitemapSet() {
        // Default constructor
    }

    /**
     * Adds a sitemap to this set.
     * @param sitemap the sitemap to add
     */

    assertThrows(
        NullPointerException.class,
        () -> {
          Object unused = getSubjectGenerator().create(array);
        });
  }

  /**
   * Returns the {@link Method} instance for {@link #testCreateWithNull_unsupported()} so that tests
   * can suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()} until <a
   * href="https://bugs.openjdk.org/browse/JDK-5045147">JDK-5045147</a> is fixed.

En realidad, `Query`, `Path` y otros que verás a continuación crean objetos de subclases de una clase común `Param`, que es a su vez una subclase de la clase `FieldInfo` de Pydantic.

Y `Field` de Pydantic también regresa una instance de `FieldInfo`.

`Body` también devuelve objetos de una subclase de `FieldInfo` directamente. Y hay otros que verás más adelante que son subclases de la clase `Body`.

  // clients from directly destroying this object since it may manage its own
  // lifetime through ref counting. Thus clients MUST call Release() in order to
  // destroy an instance of this class.
  virtual void Release() = 0;

  // Creates an operation builder and ties it to this context.
  // The returned object can be used for setting operation's attributes,

    //                                                                           =========
    private static final KeyMatchDbm _instance = new KeyMatchDbm();

    private KeyMatchDbm() {
    }

    public static KeyMatchDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

  public void testCompose() {
    Function<String, String> trim = TrimStringFunction.INSTANCE;
    Predicate<String> equalsFoo = Predicates.equalTo("Foo");

   * references, which is particularly hard to quantify.
   */

  /** Creates an empty {@code CompactHashMap} instance. */
  public static <K extends @Nullable Object, V extends @Nullable Object>
      CompactHashMap<K, V> create() {
    return new CompactHashMap<>();
  }

  /**
   * Creates a {@code CompactHashMap} instance, with a high enough "initial capacity" that it
   * <i>should</i> hold {@code expectedSize} elements without growth.

    //                                                                           =========
    private static final DuplicateHostDbm _instance = new DuplicateHostDbm();

    private DuplicateHostDbm() {
    }

    public static DuplicateHostDbm getInstance() {
        return _instance;
    }

    // ===================================================================================

    //                                                                           =========
    private static final RelatedQueryDbm _instance = new RelatedQueryDbm();

    private RelatedQueryDbm() {
    }

    public static RelatedQueryDbm getInstance() {
        return _instance;
    }

    // ===================================================================================