import okio.ByteString.Companion.encodeUtf8
import okio.IOException
import okio.Source
import okio.buffer

class ResponseBodyTest {
  @Test
  fun sourceEmpty() {
    val mediaType = if (null == null) null else "any/thing; charset=${null}".toMediaType()
    val body = "".decodeHex().toResponseBody(mediaType)
    val source = body.source()
    assertThat(source.exhausted()).isTrue()
    assertThat(source.readUtf8()).isEqualTo("")
  }

/**
 * Variant of {@link SerializableTester} that does not require the reserialized object's class to be
 * identical to the original.
 *
 * @author Chris Povirk
 */
/*
 * The whole thing is really @GwtIncompatible, but GwtJUnitConvertedTestModule doesn't have a
 * parameter for non-GWT, non-test files, and it didn't seem worth adding one for this unusual case.
 */
@GwtCompatible
@NullUnmarked

    assertBasicUrlEscaper(e);

    /*
     * Specified as safe by RFC 2396 but not by java.net.URLEncoder. These tests will start failing
     * when the escaper is made compliant with RFC 2396, but that's a good thing (just change them
     * to assertUnescaped).
     */
    assertEscaping(e, "%21", '!');
    assertEscaping(e, "%28", '(');
    assertEscaping(e, "%29", ')');
    assertEscaping(e, "%7E", '~');

In previous versions of NodeJS / Browser JavaScript, you would have used "callbacks". Which leads to "callback hell".

## Coroutines { #coroutines }

## Pin your `fastapi` version { #pin-your-fastapi-version }

The first thing you should do is to "pin" the version of **FastAPI** you are using to the specific latest version that you know works correctly for your application.

For example, let's say you are using version `0.112.0` in your app.

I think `Union[SomeType, None]` is more explicit about what it means.

It's just about the words and names. But those words can affect how you and your teammates think about the code.

As an example, let's take this function:

{* ../../docs_src/python_types/tutorial009c.py hl[1,4] *}

### OpenID (not "OpenID Connect") { #openid-not-openid-connect }

There was also an "OpenID" specification. That tried to solve the same thing as **OpenID Connect**, but was not based on OAuth2.

So, it was a complete additional system.

It is not very popular or used nowadays.

## OpenAPI { #openapi }

OpenAPI (previously known as Swagger) is the open specification for building APIs (now part of the Linux Foundation).

The `scope` `dict` and `receive` function are both part of the ASGI specification.

And those two things, `scope` and `receive`, are what is needed to create a new `Request` instance.

To learn more about the `Request` check <a href="https://www.starlette.io/requests/" class="external-link" target="_blank">Starlette's docs about Requests</a>.

///

This is the basic idea. But you will probably want to take care of some additional things, like:

* Security - HTTPS
* Running on startup
* Restarts
* Replication (the number of processes running)
* Memory
* Previous steps before starting

2. By using a `with` block, we make sure that the file-like object is closed after the generator function is done. So, after it finishes sending the response.
3. This `yield from` tells the function to iterate over that thing named `file_like`. And then, for each part iterated, yield that part as coming from this generator function (`iterfile`).

    So, it is a generator function that transfers the "generating" work to something else internally.