`TestClient` основан на <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a>, и, к счастью, мы можем использовать его (`HTTPX`) напрямую для тестирования API.

## Пример { #example }

/// 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`.

    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:

<a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> がベースなので、非常に使いやすく直感的です。

これを使用すると、**FastAPI** と共に <a href="https://docs.pytest.org/" class="external-link" target="_blank">pytest</a> を直接利用できます。

## `TestClient` を使用

`TestClient` をインポートします。

`TestClient` を作成し、**FastAPI** に渡します。

`test_` から始まる名前の関数を作成します (これは `pytest` の標準的なコンベンションです)。

`httpx` と同じ様に `TestClient` オブジェクトを使用します。

process = subprocess.Popen(
    ["fastapi", "run", "docs_src/header_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:

process = subprocess.Popen(
    ["fastapi", "run", "docs_src/request_form_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:

## HTTPX { #httpx }

Incluso si tu aplicación de **FastAPI** usa funciones `def` normales en lugar de `async def`, sigue siendo una aplicación `async` por debajo.

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.

## HTTPX { #httpx }

Auch wenn Ihre **FastAPI**-Anwendung normale `def`-Funktionen anstelle von `async def` verwendet, handelt es sich darunter immer noch um eine `async`-Anwendung.