# Used mainly to close files after the request is done, dependencies are closed
# in their own AsyncExitStack
class AsyncExitStackMiddleware:
    def __init__(
        self, app: ASGIApp, context_name: str = "fastapi_middleware_astack"
    ) -> None:
        self.app = app
        self.context_name = context_name

    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
        async with AsyncExitStack() as stack:

    assert response.json() == [
        {"aliased_name": "foo", "price": None, "owner_ids": None},
        {"aliased_name": "bar", "price": 1.0, "owner_ids": None},
        {"aliased_name": "baz", "price": 2.0, "owner_ids": [1, 2, 3]},
    ]


def test_validdict():
    response = client.get("/items/validdict")
    response.raise_for_status()
    assert response.json() == {

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item = Body(
        openapi_examples={
            "normal": {
                "summary": "A normal example",

    client = TestClient(mod.app)
    return client


@pytest.mark.parametrize(
    "path,headers,expected_status,expected_response",
    [
        ("/items", None, 200, {"strange_header": None}),
        ("/items", {"X-Header": "notvalid"}, 200, {"strange_header": None}),
        (
            "/items",
            {"strange_header": "FastAPI test"},
            200,
            {"strange_header": "FastAPI test"},
        ),

class SubItem(BaseModel):
    subname: str
    sub_description: Optional[str] = None
    tags: list[str] = []
    model_config = {"json_schema_serialization_defaults_required": True}


class Item(BaseModel):
    name: str
    description: Optional[str] = None
    sub: Optional[SubItem] = None
    model_config = {"json_schema_serialization_defaults_required": True}


class WithComputedField(BaseModel):

        "required": ["p"],
        "title": body_model_name,
        "type": "object",
    }


@pytest.mark.parametrize("json", [None, {}])
@pytest.mark.parametrize(
    "path",
    ["/required-str", "/model-required-str"],
)
def test_required_str_missing(path: str, json: Union[dict[str, Any], None]):
    client = TestClient(app)
    response = client.post(path, json=json)
    assert response.status_code == 422

Tínhamos esta anotação de tipo:

//// tab | Python 3.10+

```Python
q: str | None = None
```

////

//// tab | Python 3.9+

```Python
q: Union[str, None] = None
```

////

O que faremos é envolver isso com `Annotated`, para que fique assim:

//// tab | Python 3.10+

```Python
q: Annotated[str | None] = None
```

////

//// tab | Python 3.9+

```Python

async def router_decorator_depends():
    return {"in": "router-decorator-depends"}


app.include_router(router)

client = TestClient(app)


async def overrider_dependency_simple(q: Optional[str] = None):
    return {"q": q, "skip": 5, "limit": 10}


async def overrider_sub_dependency(k: str):
    return {"k": k}


async def overrider_dependency_with_sub(msg: dict = Depends(overrider_sub_dependency)):

        for edge in edges:
            nodes.append(edge.node)
        last_edge = edges[-1]
        edges = get_graphql_sponsor_edges(settings=settings, after=last_edge.cursor)

    tiers: defaultdict[float, dict[str, SponsorEntity]] = defaultdict(dict)
    for node in nodes:
        tiers[node.tier.monthlyPriceInDollars][node.sponsorEntity.login] = (
            node.sponsorEntity
        )
    return tiers

app = FastAPI()


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},
    "bar": {"name": "Bar", "description": "The bartenders", "price": 62, "tax": 20.2},
    "baz": {"name": "Baz", "description": None, "price": 50.2, "tax": 10.5, "tags": []},
}