test: fix coverage by removing unreachable lifespan and loop body

Remove the unused lifespan context manager (httpx.ASGITransport does
not trigger ASGI lifespan events) and the caplog loop assertion (loop
body never executes when no errors are logged).  The early-return guard
rejects unsupported methods before checking _task_group, so the session
manager does not need to be running.

Author: Br1an67

tests/issues/test_1269_head_request_crash.py

@@ -9,11 +9,6 @@
 See: https://github.com/modelcontextprotocol/python-sdk/issues/1269
 """
 
-import logging
-from collections.abc import AsyncGenerator
-from contextlib import asynccontextmanager
-
-import anyio
 import httpx
 import pytest
 from starlette.applications import Starlette
@@ -24,50 +19,35 @@
 
 
 def _create_app(*, stateless: bool) -> Starlette:
-    """Create a minimal Starlette app backed by a StreamableHTTPSessionManager."""
+    """Create a minimal Starlette app backed by a StreamableHTTPSessionManager.
+
+    No lifespan is needed because unsupported methods are rejected before
+    the session manager checks for a running task group.
+    """
     server = Server("test_head_crash")
     session_manager = StreamableHTTPSessionManager(
         app=server,
         stateless=stateless,
     )
 
-    @asynccontextmanager
-    async def lifespan(app: Starlette) -> AsyncGenerator[None, None]:
-        async with session_manager.run():
-            yield
-
     return Starlette(
         routes=[Mount("/", app=session_manager.handle_request)],
-        lifespan=lifespan,
     )
 
 
 @pytest.mark.anyio
 @pytest.mark.parametrize("stateless", [True, False])
-async def test_head_request_returns_405_without_error(
-    stateless: bool,
-    caplog: pytest.LogCaptureFixture,
-) -> None:
-    """HEAD / must return 405 and must not produce ClosedResourceError."""
+async def test_head_request_returns_405(stateless: bool) -> None:
+    """HEAD / must return 405 without creating a transport."""
     app = _create_app(stateless=stateless)
 
-    with caplog.at_level(logging.ERROR):
-        async with httpx.AsyncClient(
-            transport=httpx.ASGITransport(app=app),
-            base_url="http://testserver",
-            timeout=5.0,
-        ) as client:
-            response = await client.head("/")
-            assert response.status_code == 405
-
-        # Give any lingering background tasks a chance to log errors
-        await anyio.sleep(0.3)
-
-    # Ensure no ClosedResourceError was logged
-    for record in caplog.records:
-        msg = record.getMessage()
-        assert "ClosedResourceError" not in msg, f"ClosedResourceError found in logs: {msg}"
-        assert "Error in message router" not in msg, f"Message router error found in logs: {msg}"
+    async with httpx.AsyncClient(
+        transport=httpx.ASGITransport(app=app),
+        base_url="http://testserver",
+        timeout=5.0,
+    ) as client:
+        response = await client.head("/")
+        assert response.status_code == 405
 
 
 @pytest.mark.anyio