browser.close()


process = subprocess.Popen(
    ["fastapi", "run", "docs_src/sql_databases/tutorial002.py"],
)
try:
    for _ in range(3):
        try:
            response = httpx.get("http://localhost:8000/docs")
        except httpx.ConnectError:
            time.sleep(1)
            break
    with sync_playwright() as playwright:
        run(playwright)
finally:

process = subprocess.Popen(
    ["fastapi", "run", "docs_src/cookie_param_models/tutorial001.py"]
)
try:
    for _ in range(3):
        try:
            response = httpx.get("http://localhost:8000/docs")
        except httpx.ConnectError:
            time.sleep(1)
            break
    with sync_playwright() as playwright:
        run(playwright)
finally:

It is based on [HTTPX](https://www.python-httpx.org), which in turn is designed based on Requests, so it's very familiar and intuitive.

With it, you can use [pytest](https://docs.pytest.org/) directly with **FastAPI**.

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

/// info

To use `TestClient`, first install [`httpx`](https://www.python-httpx.org).

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX { #httpx }

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

如果我们想在测试中调用异步函数，那么我们的测试函数必须是异步的。 AnyIO 为此提供了一个简洁的插件，它允许我们指定一些测试函数要异步调用。

## HTTPX { #httpx }

即使您的 **FastAPI** 应用程序使用普通的 `def` 函数而不是 `async def` ，它本质上仍是一个 `async` 异步应用程序。

`TestClient` 在内部通过一些“魔法”操作，使得您可以在普通的 `def` 测试函数中调用异步的 FastAPI 应用程序，并使用标准的 pytest。但当我们在异步函数中使用它时，这种“魔法”就不再生效了。由于测试以异步方式运行，我们无法在测试函数中继续使用 `TestClient`。

`TestClient` 是基于 [HTTPX](https://www.python-httpx.org) 的。幸运的是，我们可以直接使用它来测试 API。

## 示例 { #example }

    browser.close()


process = subprocess.Popen(
    ["fastapi", "run", "docs_src/sql_databases/tutorial001.py"],
)
try:
    for _ in range(3):
        try:
            response = httpx.get("http://localhost:8000/docs")
        except httpx.ConnectError:
            time.sleep(1)
            break
    with sync_playwright() as playwright:
        run(playwright)
finally:

process = subprocess.Popen(
    ["fastapi", "run", "docs_src/query_param_models/tutorial001.py"]
)
try:
    for _ in range(3):
        try:
            response = httpx.get("http://localhost:8000/docs")
        except httpx.ConnectError:
            time.sleep(1)
            break
    with sync_playwright() as playwright:
        run(playwright)
finally:

    "python-slugify >=8.0.4",
    "pyyaml >=5.3.1,<7.0.0",
    "typer >=0.21.1",
]
docs-tests = [
    "httpx >=0.23.0,<1.0.0",
    "ruff >=0.14.14",
    # For UJSONResponse
    "ujson >=5.8.0",
    # For ORJSONResponse
    "orjson >=3.9.3",
]
github-actions = [
    "httpx >=0.27.0,<1.0.0",
    "pydantic >=2.9.0,<3.0.0",
    "pydantic-settings >=2.1.0,<3.0.0",
    "pygithub >=2.3.0,<3.0.0",

## HTTPX { #httpx }

**FastAPI** アプリケーションが通常の `def` 関数を使っていても、その内側は依然として `async` アプリケーションです。

`TestClient` は、標準の pytest を使って通常の `def` のテスト関数から非同期の FastAPI アプリを呼び出すための「おまじない」を内部で行います。しかし、その「おまじない」はテスト関数自体が非同期の場合には機能しません。テストを非同期で実行すると、テスト関数内で `TestClient` は使えなくなります。

`TestClient` は [HTTPX](https://www.python-httpx.org) を基に作られており、幸いなことに API のテストには HTTPX を直接利用できます。

## 例 { #example }

import pytest
from httpx import ASGITransport, AsyncClient

from .main import app


@pytest.mark.anyio
async def test_root():
    async with AsyncClient(
        transport=ASGITransport(app=app), base_url="http://test"
    ) as ac:
        response = await ac.get("/")
    assert response.status_code == 200