In the case of our dependency `get_settings()`, the function doesn't even take any arguments, so it always returns the same value.

That way, it behaves almost as if it was just a global variable. But as it uses a dependency function, then we can override it easily for testing.

////

## Upgrade `pip` { #upgrade-pip }

/// tip

If you use <a href="https://github.com/astral-sh/uv" class="external-link" target="_blank">`uv`</a> you would use it to install things instead of `pip`, so you don't need to upgrade `pip`. 😎

///

If you are using `pip` to install packages (it comes by default with Python), you should **upgrade** it to the latest version.

///

## Run it { #run-it }

After that, you just need to install `pytest`.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

<div class="termy">

```console
$ pip install pytest

---> 100%
```

</div>

  /**
   * This is mutable and order matters. By default, it contains [IPv4, IPv6]. Tests may manipulate
   * it to prefer IPv6.
   */
  private var dnsResults = listOf<InetAddress>()

  @BeforeEach
  internal fun setUp() {
    val inetAddresses = InetAddress.getAllByName("localhost")
    localhostIpv4 = inetAddresses.firstOrNull { it is Inet4Address }
      ?: throw TestAbortedException()

It has the same fields as `HeroBase`, so it won't include `secret_name`.

Finally, the identity of our heroes is protected! 🥷

It also re-declares `id: int`. By doing this, we are making a **contract** with the API clients, so that they can always expect the `id` to be there and to be an `int` (it will never be `None`).

/// tip

Next, the browser would verify that the response is valid and encrypted with the right cryptographic key, etc. It would then **decrypt the response** and process it.

<img src="/img/deployment/https/https07.drawio.svg">

        final LineIterator it = new LineIterator(reader);
        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("aaa"));
        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("bbb"));
        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("ccc"));
        assertThat(it.hasNext(), is(not(true)));
    }

    /**

If you declare it as is, because it is a singular value, **FastAPI** will assume that it is a query parameter.

But you can instruct **FastAPI** to treat it as another body key using `Body`:

{* ../../docs_src/body_multiple_params/tutorial003_an_py310.py hl[23] *}

If you need to enforce it, use `OAuth2PasswordRequestFormStrict` instead of `OAuth2PasswordRequestForm`.

///

* An optional `client_id` (we don't need it for our example).
* An optional `client_secret` (we don't need it for our example).

/// info

        final Iterator<String> it = new MultiIterator<String>(list1.iterator(), list2.iterator());

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Foo"));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Bar"));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Baz"));

        assertThat(it.hasNext(), is(not(true)));
    }