fixup! feat(testing): add build_test_client async context manager

Address pre-PR review findings: use Sequence[str] for allowed_hosts,
fix confusing docstring sentence, strengthen headers test assertion,
drop redundant asyncio markers, add ImportError test for missing dep.

https://claude.ai/code/session_01UZyqrAkoJPCEz5VLerzxFv

Author: claude

src/adcp/testing/decisioning.py

@@ -34,7 +34,7 @@
 from adcp.decisioning.types import Account
 
 if TYPE_CHECKING:
-    from collections.abc import AsyncIterator, Mapping
+    from collections.abc import AsyncIterator, Mapping, Sequence
     from datetime import datetime
 
     import httpx
@@ -135,7 +135,7 @@ def build_asgi_app(
     name: str | None = None,
     advertise_all: bool = False,
     auto_emit_completion_webhooks: bool = False,
-    allowed_hosts: list[str] | None = None,
+    allowed_hosts: Sequence[str] | None = None,
     **factory_kwargs: Any,
 ) -> Any:
     """Build a Starlette ASGI app for in-process integration tests.
@@ -218,9 +218,9 @@ async def build_test_client(
             resp = await client.post("/mcp/", json=...)
 
     The context manager starts the ASGI lifespan on entry and shuts down both
-    the client and the lifespan manager on exit. The yielded
-    ``httpx.AsyncClient`` is an :class:`contextlib.AbstractAsyncContextManager`
-    result; callers use it directly as an async HTTP client.
+    the client and the lifespan manager on exit. ``build_test_client(...)``
+    itself is an ``AbstractAsyncContextManager[httpx.AsyncClient]``; the
+    yielded object is a plain ``httpx.AsyncClient``.
 
     Requires ``asgi-lifespan`` (included in ``adcp[dev]``). Raises
     :class:`ImportError` with an actionable message if it is not installed.

tests/test_testing_decisioning.py

@@ -196,31 +196,27 @@ def test_build_asgi_app_forwards_allowed_hosts() -> None:
 # ---- build_test_client ----
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_yields_httpx_async_client() -> None:
     """The context manager yields an ``httpx.AsyncClient`` instance."""
     platform = _SalesPlatformWithMethods()
     async with build_test_client(platform) as client:
         assert isinstance(client, httpx.AsyncClient)
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_default_base_url() -> None:
     """Default ``base_url="http://test"`` is used when not overridden."""
     platform = _SalesPlatformWithMethods()
     async with build_test_client(platform) as client:
         assert str(client.base_url) == "http://test"
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_custom_base_url() -> None:
     """``base_url`` override is forwarded to the client."""
     platform = _SalesPlatformWithMethods()
     async with build_test_client(platform, base_url="http://localhost") as client:
         assert str(client.base_url) == "http://localhost"
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_can_make_request() -> None:
     """The yielded client can actually reach the mounted MCP endpoint."""
     platform = _SalesPlatformWithMethods()
@@ -245,27 +241,37 @@ async def test_build_test_client_can_make_request() -> None:
     assert resp.status_code == 200
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_headers_kwarg() -> None:
-    """Default ``headers=`` are passed through to the client."""
+    """Default ``headers=`` are attached to the client — not silently dropped."""
     platform = _SalesPlatformWithMethods()
     async with build_test_client(
         platform, headers={"x-custom": "value"}
     ) as client:
-        assert isinstance(client, httpx.AsyncClient)
+        assert "x-custom" in dict(client.headers)
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_follow_redirects_default_true() -> None:
     """``follow_redirects`` defaults to ``True`` on the yielded client."""
     platform = _SalesPlatformWithMethods()
     async with build_test_client(platform) as client:
         assert client.follow_redirects is True
 
 
-@pytest.mark.asyncio
 async def test_build_test_client_follow_redirects_override() -> None:
     """``follow_redirects=False`` is respected."""
     platform = _SalesPlatformWithMethods()
     async with build_test_client(platform, follow_redirects=False) as client:
         assert client.follow_redirects is False
+
+
+def test_build_test_client_raises_import_error_without_asgi_lifespan() -> None:
+    """Missing ``asgi-lifespan`` raises ``ImportError`` with an actionable message."""
+    import sys
+    import unittest.mock
+
+    platform = _SalesPlatformWithMethods()
+    with unittest.mock.patch.dict(sys.modules, {"asgi_lifespan": None}):
+        with pytest.raises(ImportError, match="asgi-lifespan is required"):
+            import asyncio
+
+            asyncio.run(build_test_client(platform).__aenter__())