private String leave() {
    return "leave";
  }

  public final void testMutualExclusion() throws Exception {
    thread1.callAndAssertReturns(enter());
    thread2.callAndAssertBlocks(enter());
    thread1.callAndAssertReturns(leave());
    thread2.assertPriorCallReturns(enter());
  }

  public final void testTryEnter() throws Exception {
    thread1.callAndAssertReturns(true, tryEnter());

  private String leave() {
    return "leave";
  }

  public final void testMutualExclusion() throws Exception {
    thread1.callAndAssertReturns(enter());
    thread2.callAndAssertBlocks(enter());
    thread1.callAndAssertReturns(leave());
    thread2.assertPriorCallReturns(enter());
  }

  public final void testTryEnter() throws Exception {
    thread1.callAndAssertReturns(true, tryEnter());

   * methods that do not take an explicit timeout value, a single test case is generated only if the
   * implicit timeout of that method matches the given timeoutsToUse. For example, enter() is
   * treated like enter(MAX, MILLIS) and tryEnter() is treated like enter(0, MILLIS).
   */
  private static void addTests(
      TestSuite suite,
      Method method,
      Scenario scenario,
      TimeoutsToUse timeoutsToUse,

   * methods that do not take an explicit timeout value, a single test case is generated only if the
   * implicit timeout of that method matches the given timeoutsToUse. For example, enter() is
   * treated like enter(MAX, MILLIS) and tryEnter() is treated like enter(0, MILLIS).
   */
  private static void addTests(
      TestSuite suite,
      Method method,
      Scenario scenario,
      TimeoutsToUse timeoutsToUse,

                description = "Enter the git 'user.email' configuration to commit change under",
                display = ParameterDisplay.PROMPT,
                allowEmpty = true,
            )
            text(
                "confirmationCode",
                "",
                label = "Confirmation Code",
                description = "Enter the value 'startCycle' (no quotes) to confirm the promotion",

```console
// Go to the home directory
$ cd
// Create a directory for all your code projects
$ mkdir code
// Enter into that code directory
$ cd code
// Create a directory for this project
$ mkdir awesome-project
// Enter into that project directory
$ cd awesome-project
```

Result (German):

```console
// Gehe zum Home-Verzeichnis
$ cd

But in this case, the same **FastAPI** application will handle the API and the authentication.

So, let's review it from that simplified point of view:

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).

OAuth2는 backend 또는 API가 사용자를 인증하는 서버와 독립적일 수 있도록 설계되었습니다.

하지만 이 경우에는 같은 **FastAPI** 애플리케이션이 API와 인증을 모두 처리합니다.

따라서, 단순화된 관점에서 다시 정리해보면:

* 사용자가 frontend에서 `username`과 `password`를 입력하고 `Enter`를 누릅니다.
* frontend(사용자의 브라우저에서 실행됨)는 해당 `username`과 `password`를 우리 API의 특정 URL로 보냅니다(`tokenUrl="token"`로 선언됨).
* API는 `username`과 `password`를 확인하고 "token"으로 응답합니다(아직 아무것도 구현하지 않았습니다).

<div class="termy">

```console
// Go to the home directory
$ cd
// Create a directory for all your code projects
$ mkdir code
// Enter into that code directory
$ cd code
// Create a directory for this project
$ mkdir awesome-project
// Enter into that project directory
$ cd awesome-project
```

</div>

## Create a Virtual Environment { #create-a-virtual-environment }

現在回頭理解剛剛那些是什麼。

在 OAuth2 中，`password` 是處理安全與身分驗證的其中一種「流程」（flow）。

OAuth2 的設計讓後端或 API 可以獨立於執行使用者驗證的伺服器。

但在這個例子中，同一個 FastAPI 應用會同時處理 API 與驗證。

簡化來看流程如下：

- 使用者在前端輸入 `username` 與 `password`，按下 `Enter`。
- 前端（在使用者的瀏覽器中執行）把 `username` 與 `password` 傳到我們 API 的特定 URL（在程式中宣告為 `tokenUrl="token"`）。
- API 檢查 `username` 與 `password`，並回傳一個「token（權杖）」（我們還沒實作這部分）。
    - 「token（權杖）」就是一段字串，之後可用來識別並驗證此使用者。
    - 通常 token 會設定一段時間後失效。