## Using `TestClient`

/// info

To use `TestClient`, first install <a href="https://www.python-httpx.org" class="external-link" target="_blank">`httpx`</a>.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

```console
$ pip install httpx
```

///

Import `TestClient`.

from contextvars import ContextVar
from typing import Any, Awaitable, Callable, Dict, Optional

from fastapi import Depends, FastAPI, Request, Response
from fastapi.testclient import TestClient

legacy_request_state_context_var: ContextVar[Optional[Dict[str, Any]]] = ContextVar(
    "legacy_request_state_context_var", default=None
)

app = FastAPI()


async def set_up_request_state_dependency():
    request_state = {"user": "deadpond"}

from fastapi.testclient import TestClient

from docs_src.query_params_str_validations.tutorial014_an import app

client = TestClient(app)


def test_hidden_query():
    response = client.get("/items?hidden_query=somevalue")
    assert response.status_code == 200, response.text
    assert response.json() == {"hidden_query": "somevalue"}


def test_no_hidden_query():
    response = client.get("/items")

from typing import Union

from fastapi import Body, FastAPI, Query
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/query")
def read_query(q: Union[str, None]):
    return q


@app.get("/explicit-query")
def read_explicit_query(q: Union[str, None] = Query()):
    return q


@app.post("/body-embed")
def send_body_embed(b: Union[str, None] = Body(embed=True)):
    return b

import pytest
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.request_files.tutorial001_03_an_py39 import app

    client = TestClient(app)
    return client


@needs_py39
def test_post_file(tmp_path, client: TestClient):
    path = tmp_path / "test.txt"
    path.write_bytes(b"<file content>")

    with path.open("rb") as file:

from fastapi.testclient import TestClient

from docs_src.openapi_webhooks.tutorial001 import app

client = TestClient(app)


def test_get():
    response = client.get("/users/")
    assert response.status_code == 200, response.text
    assert response.json() == ["Rick", "Morty"]


def test_dummy_webhook():
    # Just for coverage
    app.webhooks.routes[0].endpoint({})


def test_openapi_schema():

from typing import Optional

import pytest
from fastapi import Cookie, FastAPI, Header, Path, Query
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/hidden_cookie")
async def hidden_cookie(
    hidden_cookie: Optional[str] = Cookie(default=None, include_in_schema=False),
):
    return {"hidden_cookie": hidden_cookie}


@app.get("/hidden_header")
async def hidden_header(

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.query_params.tutorial005 import app

client = TestClient(app)


def test_foo_needy_very():
    response = client.get("/items/foo?needy=very")
    assert response.status_code == 200
    assert response.json() == {"item_id": "foo", "needy": "very"}


def test_foo_no_needy():
    response = client.get("/items/foo")

import os
import shutil

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.additional_responses.tutorial002 import app

client = TestClient(app)


def test_path_operation():
    response = client.get("/items/foo")
    assert response.status_code == 200, response.text
    assert response.json() == {"id": "foo", "value": "there goes my hero"}


def test_path_operation_img():

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class OtherItem(BaseModel):
    price: int


@app.post("/items/")
def save_union_body(item: Union[OtherItem, Item]):
    return {"item": item}


client = TestClient(app)


def test_post_other_item():