* </ul>
 *
 * <p>The main purpose of {@link #addListener addListener} is to support this chaining. You will
 * rarely use it directly, in part because it does not provide direct access to the {@code Future}
 * result. (If you want such access, you may prefer {@link Futures#addCallback
 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * {@snippet :
 * final String name = ...;
 * inFlight.add(name);

 * </ul>
 *
 * <p>The main purpose of {@link #addListener addListener} is to support this chaining. You will
 * rarely use it directly, in part because it does not provide direct access to the {@code Future}
 * result. (If you want such access, you may prefer {@link Futures#addCallback
 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * {@snippet :
 * final String name = ...;
 * inFlight.add(name);

        createLocalArtifact("h", "1.0");
        artifactResolver.resolveTransitively(
                Collections.singleton(g), projectArtifact, remoteRepositories(), localRepository(), null);

        // we want to see all top-level thread groups
        ThreadGroup tg = Thread.currentThread().getThreadGroup();
        while (tg.getParent() == null) {
            tg = tg.getParent();
        }

        with:
          results_file: results.sarif
          results_format: sarif
          # (Optional) "write" PAT token. Uncomment the `repo_token` line below if:
          # - you want to enable the Branch-Protection check on a *public* repository, or
          # - you are installing Scorecard on a *private* repository

{* ../../docs_src/app_testing/tutorial001.py hl[2,12,15:18] *}


/// tip | Порада

Зверніть увагу, що тестові функції — це звичайні `def`, а не `async def`.

Виклики клієнта також звичайні, без використання `await`.

Це дозволяє використовувати `pytest` без зайвих ускладнень.

///

/// note | Технічні деталі

Ви також можете використовувати `from starlette.testclient import TestClient`.

   * {@code throws} clause: Some such methods can in fact throw a checked exception (e.g., by
   * calling code written in Kotlin).) Typically, we want to let a {@link Throwable} from such a
   * method propagate untouched, just as we'd typically let it do for a non-reflective call.
   * However, we can't usually write {@code throw t;} when {@code t} has a static type of {@link

   * {@code throws} clause: Some such methods can in fact throw a checked exception (e.g., by
   * calling code written in Kotlin).) Typically, we want to let a {@link Throwable} from such a
   * method propagate untouched, just as we'd typically let it do for a non-reflective call.
   * However, we can't usually write {@code throw t;} when {@code t} has a static type of {@link

Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

				t.Fatalf("unable to write previously parsed content: %s", err)
			}
		}
		if err := w.Close(); err != nil {
			t.Fatalf("Unable to write archive: %s", err)
		}

		// TODO: We may want to check if the archive roundtrips. This would require
		// taking into account addition of the two zero trailer blocks that Writer.Close
		// appends.
	})

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>⚖️ ⚙️ <code>async def</code>...</summary>

🚥 👆 📟 ⚙️ `async` / `await`, ⚙️ `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}