## Use Case { #use-case }

Let's start with an example **use case** and then see how to solve it with this.

Let's imagine that you have some **machine learning models** that you want to use to handle requests. 🤖

    @Test
    void getHostNameDelegatesToWrappedInetAddress() {
        InetAddress dummy = mock(InetAddress.class);
        when(dummy.getHostName()).thenReturn("host.example.com");
        UniAddress ua = new UniAddress(dummy);
        assertEquals("host.example.com", ua.getHostName(), "should forward hostName to underlying InetAddress");
    }

    @Test
    void getHostAddressDelegatesToWrappedInetAddress() {

 [changelog]: https://square.github.io/okhttp/changelog/
 [conscrypt]: https://github.com/google/conscrypt/
 [get_example]: https://raw.github.com/square/okhttp/master/samples/guide/src/main/java/okhttp3/guide/GetExample.java
 [kotlin]: https://kotlinlang.org/
 [okhttp3_pro]: https://raw.githubusercontent.com/square/okhttp/master/okhttp/src/main/resources/META-INF/proguard/okhttp3.pro

I'll show you how to **build your own image from scratch** to run a single Uvicorn process. It is a simple process and is probably what you would want to do when using a distributed container management system like **Kubernetes**.

## Recap { #recap }

* PodSpecs containing parent directory references such as `..` (for example, `../bar`) in hostPath volume path or in volumeMount subpaths must be changed to the simple absolute path. Backsteps `..` are no longer allowed.([#47290](https://github.com/kubernetes/kubernetes/pull/47290), [@jhorwit2](https://github.com/jhorwit2)).


### API Machinery

        // Ensures remote host name is sourced from transport and resources are closed
        when(transport.getRemoteHostName()).thenReturn("remote.example");
        String name = handle.getRemoteHostName();
        assertEquals("remote.example", name);
        // try-with-resources should close both
        verify(session).close();
        verify(transport).close();
    }

    @Test

### Use the `app.dependency_overrides` attribute { #use-the-app-dependency-overrides-attribute }

For these cases, your **FastAPI** application has an attribute `app.dependency_overrides`, it is a simple `dict`.

To override a dependency for testing, you put as a key the original dependency (a function), and as the value, your dependency override (another function).

That tells the browser to show the integrated prompt for a username and password.

Then, when you type that username and password, the browser sends them in the header automatically.

## Simple HTTP Basic Auth { #simple-http-basic-auth }

* Import `HTTPBasic` and `HTTPBasicCredentials`.
* Create a "`security` scheme" using `HTTPBasic`.
* Use that `security` with a dependency in your *path operation*.

 - Insert a debug container in clusters that don’t have ephemeral containers enabled 
 - Modify a crashing container for easier debugging by changing its image, for example to busybox, or its command, for example, to `sleep 1d` so you have time to `kubectl exec`.
 - Inspect configuration files on a node's host filesystem

///

{* ../../docs_src/extra_models/tutorial003_py310.py hl[1,14:15,18:20,33] *}


### `Union` in Python 3.10 { #union-in-python-3-10 }

In this example we pass `Union[PlaneItem, CarItem]` as the value of the argument `response_model`.