7. Here the `response_model` is using a type annotation of a list of `Author` dataclasses.

    Again, you can combine `dataclasses` with standard type annotations.

8. Notice that this *path operation function* uses regular `def` instead of `async def`.

    As always, in FastAPI you can combine `def` and `async def` as needed.

Use the `TestClient` object the same way as you do with `httpx`.

Write simple `assert` statements with the standard Python expressions that you need to check (again, standard `pytest`).

```Python hl_lines="2  12  15-18"
{!../../../docs_src/app_testing/tutorial001.py!}
```

!!! tip
    Notice that the testing functions are normal `def`, not `async def`.

            the dependency is declared again for the rest of the request (for example
            if the dependency is needed by several dependencies), the value will be
            re-used for the rest of the request.

            Set `use_cache` to `False` to disable this behavior and ensure the
            dependency is called again (if declared more than once) in the same request.
            """

And it generates OpenAPI schemas.

That's how it works in Flask, Starlette, Responder, etc.

But then, we have again the problem of having a micro-syntax, inside of a Python string (a big YAML).

<img src="/img/tutorial/path-params/image01.png">

!!! check
    Again, just with that same Python type declaration, **FastAPI** gives you automatic, interactive documentation (integrating Swagger UI).

    Notice that the path parameter is declared to be an integer.

    ```Python hl_lines="8-9  12"
    {!> ../../../docs_src/generate_clients/tutorial003.py!}
    ```

### Generate a TypeScript Client with Custom Operation IDs

Now if you generate the client again, you will see that it has the improved method names:

<img src="/img/tutorial/generate-clients/image07.png">

```

It's a different thing.

We are using colons (`:`), not equals (`=`).

And adding type hints normally doesn't change what happens from what would happen without them.

But now, imagine you are again in the middle of creating that function, but with type hints.

At the same point, you try to trigger the autocomplete with `Ctrl+Space` and you see:

<img src="/img/python-types/image02.png">

    * A "token" is just a string with some content that we can use later to verify this user.
    * Normally, a token is set to expire after some time.
        * So, the user will have to log in again at some point later.
        * And if the token is stolen, the risk is less. It is not like a permanent key that will work forever (in most of the cases).
* The frontend stores that token temporarily somewhere.

After a week, the token will be expired and the user will not be authorized and will have to sign in again to get a new token. And if the user (or a third party) tried to modify the token to change the expiration, you would be able to discover it, because the signatures would not match.

In this case, it would be better to get **one extra server** and run some processes on it so that they all have **enough RAM and CPU time**.