# Tests asynchrones { #async-tests }

Vous avez déjà vu comment tester vos applications **FastAPI** en utilisant le `TestClient` fourni. Jusqu'à présent, vous n'avez vu que comment écrire des tests synchrones, sans utiliser de fonctions `async`.

您已经了解了如何使用 `TestClient` 测试 **FastAPI** 应用程序。但是到目前为止，您只了解了如何编写同步测试，而没有使用 `async` 异步函数。

在测试中能够使用异步函数可能会很有用，比如当您需要异步查询数据库的时候。想象一下，您想要测试向 FastAPI 应用程序发送请求，然后验证您的后端是否成功在数据库中写入了正确的数据，与此同时您使用了异步的数据库的库。

让我们看看如何才能实现这一点。

## pytest.mark.anyio { #pytest-mark-anyio }

如果我们想在测试中调用异步函数，那么我们的测试函数必须是异步的。 AnyIO 为此提供了一个简洁的插件，它允许我们指定一些测试函数要异步调用。

## HTTPX { #httpx }

name: "Sync main branch"
on:
  push:
    branches:
      - master

jobs:
  sync_latest_from_upstream:
    runs-on: ubuntu-latest
    name: Sync latest commits from master branch

    steps:
      - name: Checkout target repo
        uses: actions/checkout@v2
        with:
          ref: main

      - name: Sync upstream changes
        id: sync

@app.get("/async/dict-no-response-model")
async def async_dict_no_response_model():
    return {"name": "foo", "value": 123}


@app.get("/async/dict-with-response-model", response_model=ItemOut)
async def async_dict_with_response_model(
    dep: Annotated[int, Depends(dep_b)],
):
    return {"name": "foo", "value": 123, "dep": dep}


@app.get("/async/model-no-response-model")
async def async_model_no_response_model(

class OtherDependencyError(Exception):
    pass


async def asyncgen_state(state: dict[str, str] = Depends(get_state)):
    state["/async"] = "asyncgen started"
    yield state["/async"]
    state["/async"] = "asyncgen completed"


def generator_state(state: dict[str, str] = Depends(get_state)):
    state["/sync"] = "generator started"
    yield state["/sync"]
    state["/sync"] = "generator completed"

keepalive_app = FastAPI()


@keepalive_app.get("/slow-async", response_class=EventSourceResponse)
async def slow_async_stream():
    yield {"n": 1}
    # Sleep longer than the (monkeypatched) ping interval so a keepalive
    # comment is emitted before the next item.
    await asyncio.sleep(0.3)
    yield {"n": 2}


@keepalive_app.get("/slow-sync", response_class=EventSourceResponse)
def slow_sync_stream():

app = FastAPI()


@app.get("/items/stream-bare-async")
async def stream_bare_async() -> AsyncIterable:
    yield {"name": "foo"}


@app.get("/items/stream-bare-sync")
def stream_bare_sync() -> Iterable:
    yield {"name": "bar"}


client = TestClient(app)


def test_stream_bare_async_iterable():
    response = client.get("/items/stream-bare-async")
    assert response.status_code == 200

## ty

If ty is available, use it to check types.

## Asyncer

When needing to run blocking code inside of async functions, or async code inside of blocking functions, suggest using Asyncer.

Prefer it over AnyIO or asyncio.

Install:

```bash
uv add asyncer
```

Run blocking sync code inside of async with `asyncify()`:

```python
from asyncer import asyncify
from fastapi import FastAPI

app = FastAPI()

# "/path/bar". This script uses "gsutil rsync" instead, which acts on directory
# contents. About arguments to gsutil:
# "gsutil -m rsync" runs in parallel.
# "gsutil rsync -r" is recursive and makes directories work.
# "gsutil rsync -d" is "sync and delete files from destination if not present in source"

DOWNLOADS="$(mktemp -d)"
mkdir -p "$DOWNLOADS"
gsutil -m rsync -r "$TFCI_ARTIFACT_STAGING_GCS_URI" "$DOWNLOADS"

class Item(BaseModel):
    name: str
    price: float


app = FastAPI()


@app.get("/items/stream-invalid")
async def stream_items_invalid() -> AsyncIterable[Item]:
    yield {"name": "valid", "price": 1.0}
    yield {"name": "invalid", "price": "not-a-number"}


@app.get("/items/stream-invalid-sync")
def stream_items_invalid_sync() -> Iterable[Item]:
    yield {"name": "valid", "price": 1.0}