client = TestClient(app)
    return client


@needs_py39
def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text
    assert response.json() == {"detail": "Item not found, there's only a plumbus here"}


@needs_py39
def test_get(client: TestClient):
    response = client.get("/items/plumbus")

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        ("/", 200, {"message": "Hello World"}),
        ("/nonexistent", 404, {"detail": "Not Found"}),
    ],
)
def test_get_path(path, expected_status, expected_response):
    response = client.get(path)
    assert response.status_code == expected_status

    response = client.get("/hello/", follow_redirects=False)
    assert response.status_code == 200

    response = client.get("/hello", follow_redirects=False)

    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    return hero


@app.delete("/heroes/{hero_id}")
def delete_hero(hero_id: int, session: SessionDep):
    hero = session.get(Hero, hero_id)
    if not hero:
        raise HTTPException(status_code=404, detail="Hero not found")
    session.delete(hero)
    session.commit()

**FastAPI** prendra ce modèle, générera son schéma JSON et l'inclura au bon endroit dans OpenAPI.

Par exemple, pour déclarer une autre réponse avec un code HTTP `404` et un modèle Pydantic `Message`, vous pouvez écrire :

```Python hl_lines="18 22"
{!../../docs_src/additional_responses/tutorial001.py!}
```

/// note | "Remarque"

    assert response.json() == {"id": "foo", "value": "there goes my hero"}


def test_path_operation_not_found():
    response = client.get("/items/bar")
    assert response.status_code == 404, response.text
    assert response.json() == {"message": "Item not found"}


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text

    client = TestClient(app)
    return client


def test_get_no_item(client: TestClient):
    response = client.get("/items/foo")
    assert response.status_code == 404, response.text
    assert response.json() == {"detail": "Item not found, there's only a plumbus here"}


def test_get(client: TestClient):
    response = client.get("/items/plumbus")

Os status codes na faixa dos 400 significam que houve um erro por parte do cliente.

Você se lembra de todos aqueles erros (e piadas) a respeito do "**404 Not Found**"?

## Use o `HTTPException`

Para retornar ao cliente *responses* HTTP com erros, use o `HTTPException`.

### Import `HTTPException`

```Python hl_lines="1"

    assert response.json() == {"detail": "Invalid X-Token header"}


def test_read_nonexistent_item():
    response = client.get("/items/baz", headers={"X-Token": "coneofsilence"})
    assert response.status_code == 404
    assert response.json() == {"detail": "Item not found"}


def test_create_item():
    response = client.post(
        "/items/",
        headers={"X-Token": "coneofsilence"},

    assert response.json() == {"item": "The Foo Wrestlers"}


def test_get_item_not_found_header():
    response = client.get("/items-header/bar")
    assert response.status_code == 404, response.text
    assert response.headers.get("x-error") == "There goes my error"
    assert response.json() == {"detail": "Item not found"}


def test_openapi_schema():
    response = client.get("/openapi.json")