# 測試 { #testing }

多虧了 [Starlette](https://www.starlette.dev/testclient/)，測試 **FastAPI** 應用既簡單又好用。

它是基於 [HTTPX](https://www.python-httpx.org) 打造，而 HTTPX 的設計又參考了 Requests，所以用起來非常熟悉、直覺。

借助它，你可以直接用 [pytest](https://docs.pytest.org/) 來測試 **FastAPI**。

## 使用 `TestClient` { #using-testclient }

/// info

要使用 `TestClient`，請先安裝 [`httpx`](https://www.python-httpx.org)。

請先建立並啟用一個[虛擬環境](../virtual-environments.md)，然後安裝，例如：

```console

# 测试 { #testing }

感谢 [Starlette](https://www.starlette.dev/testclient/)，测试**FastAPI** 应用轻松又愉快。

它基于 [HTTPX](https://www.python-httpx.org)，而HTTPX又是基于Requests设计的，所以很相似且易懂。

有了它，你可以直接与**FastAPI**一起使用 [pytest](https://docs.pytest.org/)。

## 使用 `TestClient` { #using-testclient }

/// info | 信息

要使用 `TestClient`，先要安装 [`httpx`](https://www.python-httpx.org)。

确保你创建并激活一个[虚拟环境](../virtual-environments.md)，然后再安装，例如：

```console

    client = TestClient(mod.app)
    client.headers.clear()
    return client


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


@workdir_lock
def test_path_operation_img(client: TestClient):
    shutil.copy("./docs/en/docs/img/favicon.png", "./image.png")

import importlib

import pytest
from dirty_equals import IsList
from fastapi.testclient import TestClient
from inline_snapshot import snapshot

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial004_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.body_nested_models.{request.param}")

from fastapi import Depends, FastAPI, Security
from fastapi.security import APIKeyCookie
from fastapi.testclient import TestClient
from inline_snapshot import snapshot
from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyCookie(name="key", auto_error=False)


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str | None = Security(api_key)):
    if oauth_header is None:
        return None

from fastapi.testclient import TestClient

from docs_src.advanced_middleware.tutorial002_py310 import app


def test_middleware():
    client = TestClient(app, base_url="http://example.com")
    response = client.get("/")
    assert response.status_code == 200, response.text
    client = TestClient(app, base_url="http://subdomain.example.com")
    response = client.get("/")
    assert response.status_code == 200, response.text

from fastapi import APIRouter, FastAPI
from fastapi.responses import HTMLResponse, JSONResponse, PlainTextResponse
from fastapi.testclient import TestClient


class OverrideResponse(JSONResponse):
    media_type = "application/x-override"


app = FastAPI()
router_a = APIRouter()
router_a_a = APIRouter()
router_a_b_override = APIRouter()  # Overrides default class
router_b_override = APIRouter()  # Overrides default class

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

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial007_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.body_nested_models.{request.param}")

    client = TestClient(mod.app)
    return client

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

from ...utils import needs_py310


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial003_py310", marks=needs_py310),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.body.{request.param}")

    client = TestClient(mod.app)
    return client

from typing import Annotated, Any

import pytest
from fastapi import Depends, FastAPI, HTTPException
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"