```

## 🔗 🔐

🔜 👥 ✍ 🔗 🔐 & 🚮 ⚫️ 🔐 👆 📱.

```Python hl_lines="19-24  27"
{!../../../docs_src/sql_databases/sql_app/tests/test_sql_app.py!}
```

!!! tip
    📟 `override_get_db()` 🌖 ⚫️❔ 🎏 `get_db()`, ✋️ `override_get_db()` 👥 ⚙️ `TestingSessionLocal` 🔬 💽 ↩️.

## 💯 📱

⤴️ 👥 💪 💯 📱 🛎.

```Python hl_lines="32-47"
{!../../../docs_src/sql_databases/sql_app/tests/test_sql_app.py!}
```

# Custom Request and APIRoute class

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

!!! danger
    This is an "advanced" feature.

    If you are just starting with **FastAPI** you might want to skip this section.

        * [Install custom exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#install-custom-exception-handlers).
        * [Override the default exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#override-the-default-exception-handlers).
        * [Re-use **FastAPI's** exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#re-use-fastapis-exception-handlers).

@needs_py310
def test_override_in_items_run():
    from docs_src.dependency_testing.tutorial001_an_py310 import test_override_in_items

    test_override_in_items()


@needs_py310
def test_override_in_items_with_q_run():
    from docs_src.dependency_testing.tutorial001_an_py310 import (
        test_override_in_items_with_q,
    )

    test_override_in_items_with_q()


@needs_py310

    return {"message": "Hello Users!", "params": commons}


client = TestClient(app)


async def override_dependency(q: Union[str, None] = None):
    return {"q": q, "skip": 5, "limit": 10}


app.dependency_overrides[common_parameters] = override_dependency


def test_override_in_items():
    response = client.get("/items/")
    assert response.status_code == 200
    assert response.json() == {

@app.get("/server-error")
def route_with_server_error():
    raise RuntimeError("Oops!")


def test_override_http_exception():
    response = client.get("/http-exception")
    assert response.status_code == 200
    assert response.json() == {"exception": "http-exception"}


def test_override_request_validation_exception():
    response = client.get("/request-validation/invalid")
    assert response.status_code == 200

TestingSessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


Base.metadata.create_all(bind=engine)


def override_get_db():
    try:
        db = TestingSessionLocal()
        yield db
    finally:
        db.close()


app.dependency_overrides[get_db] = override_get_db

client = TestClient(app)


def test_create_user():
    response = client.post(
        "/users/",

from fastapi.testclient import TestClient

from .config import Settings
from .main import app, get_settings

client = TestClient(app)


def get_settings_override():
    return Settings(admin_email="******@****.***")


app.dependency_overrides[get_settings] = get_settings_override


def test_app():
    response = client.get("/info")
    data = response.json()
    assert data == {
        "app_name": "Awesome API",

from fastapi.testclient import TestClient

from .config import Settings
from .main import app, get_settings

client = TestClient(app)


def get_settings_override():
    return Settings(admin_email="******@****.***")


app.dependency_overrides[get_settings] = get_settings_override


def test_app():
    response = client.get("/info")
    data = response.json()
    assert data == {
        "app_name": "Awesome API",

!!! info
    Of course, the actual `Content-Type` header, status code, etc, will come from the `Response` object you returned.

### Document in OpenAPI and override `Response`

If you want to override the response from inside of the function but at the same time document the "media type" in OpenAPI, you can use the `response_class` parameter AND return a `Response` object.