`TestClient` 在内部通过一些“魔法”操作，使得您可以在普通的 `def` 测试函数中调用异步的 FastAPI 应用程序，并使用标准的 pytest。但当我们在异步函数中使用它时，这种“魔法”就不再生效了。由于测试以异步方式运行，我们无法在测试函数中继续使用 `TestClient`。

`TestClient` 是基于 <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> 的。幸运的是，我们可以直接使用它来测试API。

## 示例

# Without aliases


@app.get("/required-str")
async def read_required_str(p: Annotated[str, Header()]):
    return {"p": p}


class HeaderModelRequiredStr(BaseModel):
    p: str


@app.get("/model-required-str")
async def read_model_required_str(p: Annotated[HeaderModelRequiredStr, Header()]):
    return {"p": p.p}

 * finalize statistics collection.
 *
 */
public class CrawlerStatsHelper {

    /**
     * Creates a new instance of CrawlerStatsHelper.
     */
    public CrawlerStatsHelper() {
        // Default constructor
    }

    /** Logger instance for this class. */
    private static final Logger logger = LogManager.getLogger(CrawlerStatsHelper.class);

   * {@link Predicate#apply}. Do not provide a predicate such as {@code
   * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. (See {@link
   * Iterables#filter(Iterable, Class)} for related functionality.)
   *
   * @since 14.0
   */
  public static <E extends @Nullable Object> Multiset<E> filter(

   * {@link Predicate#apply}. Do not provide a predicate such as {@code
   * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals. (See {@link
   * Iterables#filter(Iterable, Class)} for related functionality.)
   *
   * @since 14.0
   */
  public static <E extends @Nullable Object> Multiset<E> filter(

    private static final long serialVersionUID = 1L;
    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

    // ===================================================================================
    //                                                                           Attribute

         * No-op processor that returns objects unchanged.
         */
        class NoOpProcessor implements ModelObjectProcessor {
            @Override
            public <T> T process(T object) {
                return object;
            }
        }

        ServiceLoader<ModelObjectProcessor> loader = ServiceLoader.load(ModelObjectProcessor.class);
        for (ModelObjectProcessor processor : loader) {

        return switch (level) {
            case DEBUG -> Logger.LEVEL_DEBUG;
            case INFO -> Logger.LEVEL_INFO;
            case ERROR -> Logger.LEVEL_ERROR;
        };
    }

    @Nullable
    public static Path findRoot(Path topDirectory) {
        requireNonNull(topDirectory, "topDirectory");
        Path rootDirectory =
                ServiceLoader.load(RootLocator.class).iterator().next().findRoot(topDirectory);

    exec.execute(task);
    runLatch.await();
    taskLatch.countDown();

    ExecutionException e = assertThrows(ExecutionException.class, () -> task.get(5, SECONDS));
    assertThat(e).hasCauseThat().isInstanceOf(IllegalStateException.class);

    assertTrue(listenerLatch.await(5, SECONDS));
    assertTrue(task.isDone());
    assertFalse(task.isCancelled());
  }

import java.util.Arrays;

/**
 * {@link HashFunction} adapter for {@link MessageDigest} instances.
 *
 * @author Kevin Bourrillion
 * @author Dimitris Andreou
 */
@Immutable
final class MessageDigestHashFunction extends AbstractHashFunction implements Serializable {

  @SuppressWarnings("Immutable") // cloned before each use
  private final MessageDigest prototype;

  private final int bytes;