"baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}


@app.get("/items/{item_id}", response_model=Item)
async def read_item(item_id: str):
    return items[item_id]


@app.patch("/items/{item_id}", response_model=Item)
async def update_item(item_id: str, item: Item):
    stored_item_data = items[item_id]
    stored_item_model = Item(**stored_item_data)

from fastapi.testclient import TestClient

from docs_src.behind_a_proxy.tutorial004 import app

client = TestClient(app)


def test_main():
    response = client.get("/app")
    assert response.status_code == 200
    assert response.json() == {"message": "Hello World", "root_path": "/api/v1"}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200
    assert response.json() == {

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_pydanticv1, needs_pydanticv2


@pytest.fixture(name="client")
def get_client():
    from docs_src.body_updates.tutorial001 import app

    client = TestClient(app)
    return client


def test_get(client: TestClient):
    response = client.get("/items/baz")
    assert response.status_code == 200, response.text
    assert response.json() == {

from fastapi.testclient import TestClient

from ...utils import needs_py310, needs_pydanticv1, needs_pydanticv2


@pytest.fixture(name="client")
def get_client():
    from docs_src.body_updates.tutorial001_py310 import app

    client = TestClient(app)
    return client


@needs_py310
def test_get(client: TestClient):
    response = client.get("/items/baz")
    assert response.status_code == 200, response.text

Sie können `async def` oder einfach `def` verwenden.

Und Sie können Abhängigkeiten mit `async def` innerhalb normaler `def`-*Pfadoperation-Funktionen* oder `def`-Abhängigkeiten innerhalb von `async def`-*Pfadoperation-Funktionen*, usw. deklarieren.

Es spielt keine Rolle. **FastAPI** weiß, was zu tun ist.

/// note | "Hinweis"

from fastapi.testclient import TestClient

from docs_src.handling_errors.tutorial001 import app

client = TestClient(app)


def test_get_item():
    response = client.get("/items/foo")
    assert response.status_code == 200, response.text
    assert response.json() == {"item": "The Foo Wrestlers"}


def test_get_item_not_found():
    response = client.get("/items/bar")
    assert response.status_code == 404, response.text

from docs_src.query_params_str_validations.tutorial013 import app

client = TestClient(app)


def test_multi_query_values():
    url = "/items/?q=foo&q=bar"
    response = client.get(url)
    assert response.status_code == 200, response.text
    assert response.json() == {"q": ["foo", "bar"]}


def test_query_no_values():
    url = "/items/"
    response = client.get(url)

from docs_src.metadata.tutorial004 import app

client = TestClient(app)


def test_path_operations():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    response = client.get("/users/")
    assert response.status_code == 200, response.text


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

from fastapi.testclient import TestClient

from docs_src.extending_openapi.tutorial001 import app

client = TestClient(app)


def test():
    response = client.get("/items/")
    assert response.status_code == 200, response.text
    assert response.json() == [{"name": "Foo"}]


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

```

**FastAPI** 会创建一个 `BackgroundTasks` 类型的对象并作为该参数传入。

## 创建一个任务函数

创建要作为后台任务运行的函数。

它只是一个可以接收参数的标准函数。

它可以是 `async def` 或普通的 `def` 函数，**FastAPI** 知道如何正确处理。

在这种情况下，任务函数将写入一个文件（模拟发送电子邮件）。

由于写操作不使用 `async` 和 `await`，我们用普通的 `def` 定义函数：

```Python hl_lines="6-9"
{!../../docs_src/background_tasks/tutorial001.py!}
```

## 添加后台任务

在你的 *路径操作函数* 里，用 `.add_task()` 方法将任务函数传到 *后台任务* 对象中：