```Python hl_lines="2-3  23"
{!../../docs_src/wsgi/tutorial001.py!}
```

## Check it

Now, every request under the path `/v1/` will be handled by the Flask application.

And the rest will be handled by **FastAPI**.

If you run it and go to <a href="http://localhost:8000/v1/" class="external-link" target="_blank">http://localhost:8000/v1/</a> you will see the response from Flask:

```txt
Hello, World from Flask!
```

from fastapi.testclient import TestClient

from docs_src.events.tutorial003 import (
    app,
    fake_answer_to_everything_ml_model,
    ml_models,
)


def test_events():
    assert not ml_models, "ml_models should be empty"
    with TestClient(app) as client:
        assert ml_models["answer_to_everything"] == fake_answer_to_everything_ml_model
        response = client.get("/predict", params={"x": 2})

from fastapi.testclient import TestClient

from docs_src.response_model.tutorial003_02 import app

client = TestClient(app)


def test_get_portal():
    response = client.get("/portal")
    assert response.status_code == 200, response.text
    assert response.json() == {"message": "Here's your interdimensional portal."}


def test_get_redirect():
    response = client.get("/portal", params={"teleport": True}, follow_redirects=False)

You could also use `from starlette.testclient import TestClient`.

**FastAPI** provides the same `starlette.testclient` as `fastapi.testclient` just as a convenience for you, the developer. But it comes directly from Starlette.

///

/// tip

from typing import Optional

from dirty_equals import IsDict
from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()


@app.get(
    "/",
    openapi_extra={
        "parameters": [
            {
                "required": False,
                "schema": {"title": "Extra Param 1"},
                "name": "extra_param_1",
                "in": "query",
            },
            {

from typing import Optional

from fastapi import Depends, FastAPI, Query, status
from fastapi.testclient import TestClient

app = FastAPI()


def _get_client_key(client_id: str = Query(...)) -> str:
    return f"{client_id}_key"


def _get_client_tag(client_id: Optional[str] = Query(None)) -> Optional[str]:
    if client_id is None:
        return None
    return f"{client_id}_tag"


@app.get("/foo")
def foo_handler(

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py39, needs_pydanticv1, needs_pydanticv2


@pytest.fixture(name="client")
def get_client():
    from docs_src.body_updates.tutorial001_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_get(client: TestClient):
    response = client.get("/items/baz")
    assert response.status_code == 200, response.text

import json
from typing import Dict

import pytest
from fastapi import BackgroundTasks, Depends, FastAPI
from fastapi.responses import StreamingResponse
from fastapi.testclient import TestClient

app = FastAPI()
state = {
    "/async": "asyncgen not started",
    "/sync": "generator not started",
    "/async_raise": "asyncgen raise not started",
    "/sync_raise": "generator raise not started",
    "context_a": "not started a",

from typing import Union

from fastapi import FastAPI
from fastapi.encoders import jsonable_encoder
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Union[str, None] = None
    description: Union[str, None] = None
    price: Union[float, None] = None
    tax: float = 10.5
    tags: list[str] = []


items = {
    "foo": {"name": "Foo", "price": 50.2},

⭕ 📨, 📨 `Response` 🔗 🌅 ⏩ 🌘 🛬 📖.

👉 ↩️ 🔢, FastAPI 🔜 ✔ 🔠 🏬 🔘 & ⚒ 💭 ⚫️ 🎻 ⏮️ 🎻, ⚙️ 🎏 [🎻 🔗 🔢](../tutorial/encoder.md){.internal-link target=_blank} 🔬 🔰. 👉 ⚫️❔ ✔ 👆 📨 **❌ 🎚**, 🖼 💽 🏷.

✋️ 🚥 👆 🎯 👈 🎚 👈 👆 🛬 **🎻 ⏮️ 🎻**, 👆 💪 🚶‍♀️ ⚫️ 🔗 📨 🎓 & ❎ ➕ 🌥 👈 FastAPI 🔜 ✔️ 🚶‍♀️ 👆 📨 🎚 🔘 `jsonable_encoder` ⏭ 🚶‍♀️ ⚫️ 📨 🎓.

```Python hl_lines="2  7"
{!../../docs_src/custom_response/tutorial001b.py!}