✍ 🙅 `assert` 📄 ⏮️ 🐩 🐍 🧬 👈 👆 💪 ✅ (🔄, 🐩 `pytest`).

```Python hl_lines="2  12  15-18"
{!../../docs_src/app_testing/tutorial001.py!}
```

/// tip

👀 👈 🔬 🔢 😐 `def`, 🚫 `async def`.

 & 🤙 👩‍💻 😐 🤙, 🚫 ⚙️ `await`.

👉 ✔ 👆 ⚙️ `pytest` 🔗 🍵 🤢.

///

/// note | "📡 ℹ"

👆 💪 ⚙️ `from starlette.testclient import TestClient`.

    price: float
    tax: Union[float, None] = None


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: int = Body(gt=0),
    q: Union[str, None] = None,
):

import os
from pathlib import Path

from fastapi.testclient import TestClient

from ...utils import needs_py310


@needs_py310
def test():
    from docs_src.background_tasks.tutorial002_an_py310 import app

    client = TestClient(app)
    log = Path("log.txt")
    if log.is_file():
        os.remove(log)  # pragma: no cover
    response = client.post("/send-notification/******@****.***?q=some-query")

import os
from pathlib import Path

from fastapi.testclient import TestClient

from ...utils import needs_py39


@needs_py39
def test():
    from docs_src.background_tasks.tutorial002_an_py39 import app

    client = TestClient(app)
    log = Path("log.txt")
    if log.is_file():
        os.remove(log)  # pragma: no cover
    response = client.post("/send-notification/******@****.***?q=some-query")

    price: float
    tax: Union[float, None] = None


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: Annotated[int, Body(gt=0)],
    q: Union[str, None] = None,
):

    price: float
    tax: Union[float, None] = None


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: Annotated[int, Body(gt=0)],
    q: Union[str, None] = None,
):

        "email": "******@****.***",
    },
    license_info={
        "name": "Apache 2.0",
        "identifier": "MIT",
    },
)


@app.get("/items/")
async def read_items():

@app.post(
    "/items/",
    openapi_extra={
        "requestBody": {
            "content": {"application/x-yaml": {"schema": Item.model_json_schema()}},
            "required": True,
        },
    },
)
async def create_item(request: Request):
    raw_body = await request.body()
    try:
        data = yaml.safe_load(raw_body)
    except yaml.YAMLError:
        raise HTTPException(status_code=422, detail="Invalid YAML")
    try:

```

...& ↩️ 👥 ⚙️:

```Python
user = db.query(User).first()
```

⤴️ 👥 🔜 📣 *➡ 🛠️ 🔢* & 🔗 🍵 `async def`, ⏮️ 😐 `def`,:

```Python hl_lines="2"
@app.get("/users/{user_id}", response_model=schemas.User)
def read_user(user_id: int, db: Session = Depends(get_db)):
    db_user = crud.get_user(db, user_id=user_id)
    ...
```

/// info

Elle sera appelée par **FastAPI** quand une requête sur l'URL `/` sera reçue via une opération `GET`.

Ici, c'est une fonction asynchrone (définie avec `async def`).

---

Vous pourriez aussi la définir comme une fonction classique plutôt qu'avec `async def` :

```Python hl_lines="7"
{!../../docs_src/first_steps/tutorial003.py!}
```

/// note