if (expected != actual) {
      fail("Expected for " + a + " " + op + " " + b + " = " + expected + ", but got " + actual);
    }
  }

  // Depends on the correctness of BigIntegerMath.factorial.
  @GwtIncompatible // TODO
  public void testFactorial() {
    for (int n = 0; n <= 50; n++) {
      BigInteger expectedBig = BigIntegerMath.factorial(n);

 * invoke methods, they invoke methods on the {@code ForwardingMultiset}.
 *
 * <p>The {@code standard} methods and any collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
public abstract class ForwardingMultiset<E extends @Nullable Object> extends ForwardingCollection<E>

 * not consistent with {@code equals}.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be
 * thread-safe, even when all of the methods that they depend on are thread-safe.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible

現在用 **FastAPI** 提供的工具來處理。

### `OAuth2PasswordRequestForm` { #oauth2passwordrequestform }

先匯入 `OAuth2PasswordRequestForm`，並在 `/token` 的路徑操作中，搭配 `Depends` 當作依賴使用：

{* ../../docs_src/security/tutorial003_an_py310.py hl[4,78] *}

`OAuth2PasswordRequestForm` 是一個類別型依賴，它宣告了一個表單本文，包含：

- `username`
- `password`
- 可選的 `scope` 欄位，內容是一個由空白分隔的長字串
- 可選的 `grant_type`

    initialize the response cache.
 *  New: Fold `MockWebServerRule` into `MockWebServer`. This makes it easier to
    write JUnit tests with `MockWebServer`. The `MockWebServer` library now
    depends on JUnit, though it continues to work with all testing frameworks.
 *  Fix: `FormEncodingBuilder` is now consistent with browsers in which
    characters it escapes. Previously we weren’t percent-encoding commas,

        assertEquals("http://example.com/%7Bid%7D", result);
    }

    @Test
    public void test_encodeUrl_unicodeChars() {
        // Non-ASCII characters are percent-encoded; encoding depends on request context
        String result = DocumentUtil.encodeUrl("http://example.com/\u00D6sterreich");
        assertEquals("http://example.com/%D6sterreich", result);
    }

    @Test

   * the caller when the timeout elapses; aborting the target method call is of secondary concern.
   * The particular nature and strength of the guarantees made by the proxy is
   * implementation-dependent. However, it is important that each of the methods on the target
   * object behaves appropriately when its thread is interrupted.
   *
   * <p>For example, to return the value of {@code target.someMethod()}, but substitute {@code

  ConcurrentMap<K, V> asMap();

  /**
   * Performs any pending maintenance operations needed by the cache. Exactly which activities are
   * performed -- if any -- is implementation-dependent.
   */
  void cleanUp();

   *
   * <p><b>Warning: do not depend</b> on the behavior of this method.
   *
   * <p>Historically, {@code Converter} instances in this library have implemented this method to
   * recognize certain cases where distinct {@code Converter} instances would in fact behave
   * identically. However, this is not true of {@code Converter} implementations in general. It is
   * best not to depend on it.
   */
  @Override

接下来，使用 **FastAPI** 工具获取用户名与密码。

### `OAuth2PasswordRequestForm` { #oauth2passwordrequestform }

首先，导入 `OAuth2PasswordRequestForm`，然后，在 `/token` *路径操作* 中，用 `Depends` 把该类作为依赖项。

{* ../../docs_src/security/tutorial003_an_py310.py hl[4,78] *}

`OAuth2PasswordRequestForm` 是用以下几项内容声明表单请求体的类依赖项：

* `username`
* `password`
* 可选的 `scope` 字段，由多个空格分隔的字符串组成的长字符串
* 可选的 `grant_type`