self.name = name


app = FastAPI()


@app.exception_handler(UnicornException)
async def unicorn_exception_handler(request: Request, exc: UnicornException):
    return JSONResponse(
        status_code=418,
        content={"message": f"Oops! {exc.name} did something. There goes a rainbow..."},
    )


@app.get("/unicorns/{name}")
async def read_unicorn(name: str):
    if name == "yolo":

from fastapi.testclient import TestClient


class CustomError(Exception):
    pass


def catching_dep() -> Any:
    try:
        yield "s"
    except CustomError as err:
        raise HTTPException(status_code=418, detail="Session error") from err


def broken_dep() -> Any:
    yield "s"
    raise ValueError("Broken after yield")


app = FastAPI()


@app.get("/catching")

app.include_router(users.router)
app.include_router(items.router)
app.include_router(
    admin.router,
    prefix="/admin",
    tags=["admin"],
    dependencies=[Depends(get_token_header)],
    responses={418: {"description": "I'm a teapot"}},
)


@app.get("/")
async def root():

app.include_router(users.router)
app.include_router(items.router)
app.include_router(
    admin.router,
    prefix="/admin",
    tags=["admin"],
    dependencies=[Depends(get_token_header)],
    responses={418: {"description": "I'm a teapot"}},
)


@app.get("/")
async def root():

    return await request_validation_exception_handler(request, exc)


@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id == 3:
        raise HTTPException(status_code=418, detail="Nope! I don't like 3.")

    return PlainTextResponse(message, status_code=400)


@app.get("/items/{item_id}")
async def read_item(item_id: int):
    if item_id == 3:
        raise HTTPException(status_code=418, detail="Nope! I don't like 3.")

                "input": "foo",
            }
        ]
    }


def test_get_http_error():
    response = client.get("/items/3")
    assert response.status_code == 418, response.text
    assert response.json() == {"detail": "Nope! I don't like 3."}


def test_get():
    response = client.get("/items/2")
    assert response.status_code == 200, response.text

    assert response.status_code == 200, response.text
    assert response.json() == {"unicorn_name": "shinny"}


def test_get_exception():
    response = client.get("/unicorns/yolo")
    assert response.status_code == 418, response.text
    assert response.json() == {
        "message": "Oops! yolo did something. There goes a rainbow..."
    }


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

    assert "Validation errors:" in response.text
    assert "Field: ('path', 'item_id')" in response.text


def test_get_http_error():
    response = client.get("/items/3")
    assert response.status_code == 418, response.text
    assert response.content == b"Nope! I don't like 3."


def test_get():
    response = client.get("/items/2")
    assert response.status_code == 200, response.text

Aquí, si solicitas `/unicorns/yolo`, la *path operation* lanzará un `UnicornException`.

Pero será manejado por el `unicorn_exception_handler`.

Así que recibirás un error limpio, con un código de estado HTTP de `418` y un contenido JSON de:

```JSON
{"message": "Oops! yolo did something. There goes a rainbow..."}
```

/// note | Nota Técnica