assert response.status_code == 200, response.text
    assert response.json() == {"message": "No file sent"}


def test_post_uploadfile_no_body():
    response = client.post("/uploadfile/")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "No upload file sent"}


def test_post_file(tmp_path):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")

You will also get autocompletion for the payload to send:

<img src="/img/tutorial/generate-clients/image03.png">

!!! tip
    Notice the autocompletion for `name` and `price`, that was defined in the FastAPI application, in the `Item` model.

You will have inline errors for the data that you send:

<img src="/img/tutorial/generate-clients/image04.png">

        dep -->> handler: Auto forward exception
    end
    operation ->> client: Return response to client
    Note over client,operation: Response is already sent, can't change it anymore
    opt Tasks
        operation -->> tasks: Send background tasks
    end
    opt Raise other exception
        tasks -->> dep: Raise other exception
    end
    Note over dep: After yield
    opt Handle other exception

In that case, it would mean the JSON attributes, and data types they have, etc.

#### OpenAPI and JSON Schema

OpenAPI defines an API schema for your API. And that schema includes definitions (or "schemas") of the data sent and received by your API using **JSON Schema**, the standard for JSON data schemas.

#### Check the `openapi.json`

  "full_name": "John Doe",
  "disabled": false
}
```

<img src="/img/tutorial/security/image09.png">

If you open the developer tools, you could see how the data sent only includes the token, the password is only sent in the first request to authenticate the user and get that access token, but not afterwards:

<img src="/img/tutorial/security/image10.png">

!!! note

    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: Union[UploadFile, None] = None):
    if not file:
        return {"message": "No upload file sent"}
    else:

            email_file.write(content)


    @app.post("/send-notification/{email}")
    async def send_notification(email: str, background_tasks: BackgroundTasks):
        background_tasks.add_task(write_notification, email, message="some notification")
        return {"message": "Notification sent in the background"}
    ```
    """

    def add_task(
        self,
        func: Annotated[

One of the main features needed by API systems is data "<abbr title="also called marshalling, conversion">serialization</abbr>" which is taking data from the code (Python) and converting it into something that can be sent through the network. For example, converting an object containing data from a database into a JSON object. Converting `datetime` objects into strings, etc.

        background_tasks.add_task(write_log, message)
    return q


@app.post("/send-notification/{email}")
async def send_notification(
    email: str, background_tasks: BackgroundTasks, q: Annotated[str, Depends(get_query)]
):
    message = f"message to {email}\n"
    background_tasks.add_task(write_log, message)

    if not file:
        return {"message": "No file sent"}
    else:
        return {"file_size": len(file)}


@app.post("/uploadfile/")
async def create_upload_file(file: Union[UploadFile, None] = None):
    if not file:
        return {"message": "No upload file sent"}
    else: