# Testing WebSockets

You can use the same `TestClient` to test WebSockets.

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

```Python hl_lines="27-31"
{!../../docs_src/app_testing/tutorial002.py!}
```

/// note

For more details, check Starlette's documentation for <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testing WebSockets</a>.

The `TestClient` is based on <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, and luckily, we can use it directly to test the API.

## Example

# despite lacking Nvidia CUDA support.
TFCI_BUILD_PIP_PACKAGE_ARGS="--repo_env=WHEEL_NAME=tensorflow"
TFCI_DOCKER_ENABLE=1
TFCI_DOCKER_IMAGE=us-central1-docker.pkg.dev/tensorflow-sigs/tensorflow/build-arm64:tf-2-18-multi-python
TFCI_DOCKER_PULL_ENABLE=1
TFCI_DOCKER_REBUILD_ARGS="--target=tf ci/official/containers/linux_arm64"
TFCI_INDEX_HTML_ENABLE=1
TFCI_LIB_SUFFIX="-cpu-linux-arm64"
TFCI_OUTPUT_DIR=build_output
TFCI_WHL_AUDIT_ENABLE=1

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

    ## Usage

    Create an instance object and use that object as the dependency in `Depends()`.

    The dependency result will be a string containing the key value.

    ## Example

    ```python
    from fastapi import Depends, FastAPI
    from fastapi.security import APIKeyQuery

    app = FastAPI()

    query_scheme = APIKeyQuery(name="api_key")


    @app.get("/items/")

/pip_test
/_python_build
*.pyc
__pycache__
*.swp
.vscode/
cmake_build/
tensorflow/contrib/cmake/_build/
.idea/**
/build/
[Bb]uild/
/build_output/
/tensorflow/core/util/version_info.cc
/tensorflow/python/framework/fast_tensor_util.cpp
/tensorflow/lite/gen/**
/tensorflow/lite/tools/make/downloads/**
/tensorflow/lite/tools/make/gen/**
/api_init_files_list.txt
/estimator_api_init_files_list.txt
*.whl
dist

# WebSockets testen

Sie können den schon bekannten `TestClient` zum Testen von WebSockets verwenden.

Dazu verwenden Sie den `TestClient` in einer `with`-Anweisung, eine Verbindung zum WebSocket herstellend:

```Python hl_lines="27-31"
{!../../docs_src/app_testing/tutorial002.py!}
```

/// note | "Hinweis"

Puedes declarar un parámetro de tipo `Response` en tu *función de operación de path* (de manera similar como se hace con las cookies).

Y entonces, podrás configurar las cookies en ese objeto de response *temporal*.

```Python hl_lines="1  7-8"
{!../../docs_src/response_headers/tutorial002.py!}
```

Posteriormente, puedes devolver cualquier objeto que necesites, como normalmente harías (un `dict`, un modelo de base de datos, etc).

* **Pronto para Produção** com servidor _web_ usando Uvicorn e Gunicorn.
* _Backend_ <a href="https://github.com/fastapi/fastapi" class="external-link" target="_blank">**FastAPI**</a> Python:
    * **Rápido**: Alta performance, no nível de **NodeJS** e **Go** (graças ao Starlette e Pydantic).

In diesen Fällen können Sie den `jsonable_encoder` verwenden, um Ihre Daten zu konvertieren, bevor Sie sie an eine Response übergeben:

```Python hl_lines="6-7  21-22"
{!../../docs_src/response_directly/tutorial001.py!}
```

/// note | "Technische Details"

Sie können auch `from starlette.responses import JSONResponse` verwenden.