You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

from starlette.testclient import TestClient as TestClient  # noqa...

"""

from typing import Annotated

from fastapi import BackgroundTasks, Depends, FastAPI, Request, Response
from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient


def test_response_with_depends_annotated():
    """Response type hint should work with Annotated[Response, Depends(...)]."""
    app = FastAPI()

    def modify_response(response: Response) -> Response:

@pytest.fixture(name="client")
def client_fixture() -> TestClient:
    app = FastAPI()

    @app.get("/")
    async def get_people(client: Client) -> list:
        return await client.get_people()

    client = TestClient(app)
    return client


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

    async def read_root() -> Any:
        return {"$ref": "some-ref"}

    client = TestClient(app)
    return client


def test_get(client: TestClient):
    response = client.get("/")
    assert response.json() == {"$ref": "some-ref"}


def test_openapi_schema(client: TestClient):
    response = client.get("openapi.json")
    assert response.json() == snapshot(
        {

import pytest
from fastapi import FastAPI
from fastapi.testclient import TestClient
from inline_snapshot import snapshot


@pytest.fixture(name="client")
def get_client(request):
    separate_input_output_schemas = request.param
    app = FastAPI(separate_input_output_schemas=separate_input_output_schemas)

    from pydantic import BaseModel, computed_field

    class Rectangle(BaseModel):
        width: int
        length: int

import warnings

import pytest
from fastapi import FastAPI
from fastapi.exceptions import FastAPIDeprecationWarning
from fastapi.responses import ORJSONResponse, UJSONResponse
from fastapi.testclient import TestClient
from pydantic import BaseModel


class Item(BaseModel):
    name: str
    price: float


# ORJSON


def _make_orjson_app() -> FastAPI:
    with warnings.catch_warnings():

from fastapi import FastAPI
from fastapi.testclient import TestClient

app = FastAPI()

items = {}


@app.on_event("startup")
async def startup_event():
    items["foo"] = {"name": "Fighters"}
    items["bar"] = {"name": "Tenders"}


@app.get("/items/{item_id}")
async def read_items(item_id: str):
    return items[item_id]


def test_read_items():
    with TestClient(app) as client:

import warnings

from fastapi import FastAPI
from fastapi.exceptions import FastAPIDeprecationWarning
from fastapi.responses import ORJSONResponse
from fastapi.testclient import TestClient
from sqlalchemy.sql.elements import quoted_name

with warnings.catch_warnings():
    warnings.simplefilter("ignore", FastAPIDeprecationWarning)
    app = FastAPI(default_response_class=ORJSONResponse)


@app.get("/orjson_non_str_keys")

from fastapi import FastAPI
from fastapi.testclient import TestClient


def test_root_path_does_not_persist_across_requests():
    app = FastAPI()

    @app.get("/")
    def read_root():  # pragma: no cover
        return {"ok": True}

    # Attacker request with a spoofed root_path
    attacker_client = TestClient(app, root_path="/evil-api")
    response1 = attacker_client.get("/openapi.json")
    data1 = response1.json()