From e5a0c6f21130265514112f290975bf02ce80c0cd Mon Sep 17 00:00:00 2001 From: Guillaume Fassot <97948781+prometek@users.noreply.github.com> Date: Tue, 24 Sep 2024 20:34:44 +0200 Subject: [PATCH] copy async-tests.md from docs/en/docs/advanced --- docs/fr/docs/advanced/async-tests.md | 107 +++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 docs/fr/docs/advanced/async-tests.md diff --git a/docs/fr/docs/advanced/async-tests.md b/docs/fr/docs/advanced/async-tests.md new file mode 100644 index 000000000..a528c80fe --- /dev/null +++ b/docs/fr/docs/advanced/async-tests.md @@ -0,0 +1,107 @@ +# Async Tests + +You have already seen how to test your **FastAPI** applications using the provided `TestClient`. Up to now, you have only seen how to write synchronous tests, without using `async` functions. + +Being able to use asynchronous functions in your tests could be useful, for example, when you're querying your database asynchronously. Imagine you want to test sending requests to your FastAPI application and then verify that your backend successfully wrote the correct data in the database, while using an async database library. + +Let's look at how we can make that work. + +## pytest.mark.anyio + +If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously. + +## HTTPX + +Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath. + +The `TestClient` does some magic inside to call the asynchronous FastAPI application in your normal `def` test functions, using standard pytest. But that magic doesn't work anymore when we're using it inside asynchronous functions. By running our tests asynchronously, we can no longer use the `TestClient` inside our test functions. + +The `TestClient` is based on HTTPX, and luckily, we can use it directly to test the API. + +## Example + +For a simple example, let's consider a file structure similar to the one described in [Bigger Applications](../tutorial/bigger-applications.md){.internal-link target=_blank} and [Testing](../tutorial/testing.md){.internal-link target=_blank}: + +``` +. +├── app +│   ├── __init__.py +│   ├── main.py +│   └── test_main.py +``` + +The file `main.py` would have: + +```Python +{!../../../docs_src/async_tests/main.py!} +``` + +The file `test_main.py` would have the tests for `main.py`, it could look like this now: + +```Python +{!../../../docs_src/async_tests/test_main.py!} +``` + +## Run it + +You can run your tests as usual via: + +
+ +```console +$ pytest + +---> 100% +``` + +
+ +## In Detail + +The marker `@pytest.mark.anyio` tells pytest that this test function should be called asynchronously: + +```Python hl_lines="7" +{!../../../docs_src/async_tests/test_main.py!} +``` + +/// tip + +Note that the test function is now `async def` instead of just `def` as before when using the `TestClient`. + +/// + +Then we can create an `AsyncClient` with the app, and send async requests to it, using `await`. + +```Python hl_lines="9-12" +{!../../../docs_src/async_tests/test_main.py!} +``` + +This is the equivalent to: + +```Python +response = client.get('/') +``` + +...that we used to make our requests with the `TestClient`. + +/// tip + +Note that we're using async/await with the new `AsyncClient` - the request is asynchronous. + +/// + +/// warning + +If your application relies on lifespan events, the `AsyncClient` won't trigger these events. To ensure they are triggered, use `LifespanManager` from florimondmanca/asgi-lifespan. + +/// + +## Other Asynchronous Function Calls + +As the testing function is now asynchronous, you can now also call (and `await`) other `async` functions apart from sending requests to your FastAPI application in your tests, exactly as you would call them anywhere else in your code. + +/// tip + +If you encounter a `RuntimeError: Task attached to a different loop` when integrating asynchronous function calls in your tests (e.g. when using MongoDB's MotorClient), remember to instantiate objects that need an event loop only within async functions, e.g. an `'@app.on_event("startup")` callback. + +///