httpx==0.28.0 seems to be incompatible with starlette's TestClient

[josealeixopc]

Hey folks.

On a service of mine, I have starlette==0.36.3. Recently, with the release of httpx==0.28.0, tests using TestClient broke with the following error:

self = <starlette.testclient.TestClient object at 0x7faff0178710>

    def __init__(
        self,
        app: ASGIApp,
        base_url: str = "http://testserver",
        raise_server_exceptions: bool = True,
        root_path: str = "",
        backend: typing.Literal["asyncio", "trio"] = "asyncio",
        backend_options: dict[str, typing.Any] | None = None,
        cookies: httpx._types.CookieTypes | None = None,
        headers: dict[str, str] | None = None,
        follow_redirects: bool = True,
    ) -> None:
        self.async_backend = _AsyncBackend(
            backend=backend, backend_options=backend_options or {}
        )
        if _is_asgi3(app):
            asgi_app = app
        else:
            app = typing.cast(ASGI2App, app)  # type: ignore[assignment]
            asgi_app = _WrapASGI2(app)  # type: ignore[arg-type]
        self.app = asgi_app
        self.app_state: dict[str, typing.Any] = {}
        transport = _TestClientTransport(
            self.app,
            portal_factory=self._portal_factory,
            raise_server_exceptions=raise_server_exceptions,
            root_path=root_path,
            app_state=self.app_state,
        )
        if headers is None:
            headers = {}
        headers.setdefault("user-agent", "testclient")
>       super().__init__(
            app=self.app,
            base_url=base_url,
            headers=headers,
            transport=transport,
            follow_redirects=follow_redirects,
            cookies=cookies,
        )
E       TypeError: Client.__init__() got an unexpected keyword argument 'app'

I assume this means that the TestClient from starlette is not compatible with the new httpx.Client. Anyone else able to reproduce this?

[Kludex]

cc @tomchristie

[tomchristie]

Hi app is deprecated and its usage raises warnings since version 0.27.0.

[tomchristie]

(You can either upgrade Starlette, since it looks to me like the current version doesn't have this issue, or pin your httpx dependency)

[josealeixopc]

Thanks for clarifying! Indeed I see this was changed here. Will try to update starlette to at least 0.37.2. I'll report back when I do.

[tomchristie]

Useful feedback here...

• DeprecationWarning
• RuntimeError
• Removal

Likely more helpful for our users.

(Or else more generally figuring out how we guiderail our users into neatly pinned dependencies)