test(mcp): drive ASGI app directly, skip Quart test_client

Quart's test_client expects its request pipeline to populate
app._preserved_context. Our /mcp middleware deliberately bypasses
that pipeline (forwarding straight to FastMCP), so test_client's
teardown blew up with AttributeError. The middleware is correct;
the test harness was wrong.

Build raw ASGI scope/receive/send and call app.asgi_app directly —
which is what production hypercorn does anyway.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_mcp_endpoint.py

@@ -1,9 +1,16 @@
 """End-to-end tests for the /mcp HTTP endpoint mounted on the Quart app.
 
-These exercise the ASGI dispatch + auth middleware. The api_keys lookup is
-mocked so the tests don't require a database, matching the pattern in
-test_api_keys.py.
+These exercise the ASGI dispatch + auth middleware by driving the app's ASGI
+callable directly. We avoid Quart's test_client() because it expects Quart's
+request pipeline to set `app._preserved_context` as a side effect, but our
+ASGI middleware forwards /mcp requests to FastMCP without touching the Quart
+pipeline (correct production behavior), which causes test_client to fail on
+teardown.
+
+The api_keys lookup is mocked so the tests don't require a database, matching
+the pattern in test_api_keys.py.
 """
+import json
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
@@ -11,15 +18,55 @@ import pytest
 from fabledassistant.app import create_app
 
 
+async def _send_request(
+    app, method: str, path: str,
+    headers: dict | None = None, body: bytes | None = None,
+) -> tuple[int, bytes]:
+    """Drive the app's ASGI callable directly and collect the response."""
+    raw_headers = [(k.lower().encode(), v.encode()) for k, v in (headers or {}).items()]
+    if body is not None:
+        raw_headers.append((b"content-length", str(len(body)).encode()))
+    scope = {
+        "type": "http",
+        "asgi": {"version": "3.0", "spec_version": "2.3"},
+        "http_version": "1.1",
+        "method": method,
+        "scheme": "http",
+        "path": path,
+        "raw_path": path.encode(),
+        "query_string": b"",
+        "root_path": "",
+        "headers": raw_headers,
+        "client": ("testclient", 50000),
+        "server": ("testserver", 80),
+    }
+    receive_messages = [{
+        "type": "http.request", "body": body or b"", "more_body": False,
+    }]
+    sent: list[dict] = []
+
+    async def receive():
+        if receive_messages:
+            return receive_messages.pop(0)
+        return {"type": "http.disconnect"}
+
+    async def send(message):
+        sent.append(message)
+
+    await app.asgi_app(scope, receive, send)
+
+    start = next(m for m in sent if m["type"] == "http.response.start")
+    body_chunks = b"".join(
+        m.get("body", b"") for m in sent if m["type"] == "http.response.body"
+    )
+    return start["status"], body_chunks
+
+
 @pytest.mark.asyncio
 async def test_mcp_endpoint_unauthenticated_returns_401():
     app = create_app()
-    async with app.test_client() as client:
-        resp = await client.post(
-            "/mcp",
-            json={"jsonrpc": "2.0", "id": 1, "method": "ping"},
-        )
-    assert resp.status_code == 401
+    status, _ = await _send_request(app, "POST", "/mcp")
+    assert status == 401
 
 
 @pytest.mark.asyncio
@@ -29,56 +76,48 @@ async def test_mcp_endpoint_invalid_token_returns_401():
         "fabledassistant.mcp.auth.lookup_key",
         AsyncMock(return_value=None),
     ):
-        async with app.test_client() as client:
-            resp = await client.post(
-                "/mcp",
-                json={"jsonrpc": "2.0", "id": 1, "method": "ping"},
-                headers={"Authorization": "Bearer fmcp_invalid"},
-            )
-    assert resp.status_code == 401
+        status, _ = await _send_request(
+            app, "POST", "/mcp",
+            headers={"Authorization": "Bearer fmcp_invalid"},
+        )
+    assert status == 401
 
 
 @pytest.mark.asyncio
 async def test_mcp_endpoint_valid_token_passes_auth():
-    """With a valid Bearer, the request reaches FastMCP. FastMCP may return
-    200 (initialize handshake), 400, or a streaming response — anything other
-    than 401 confirms auth passed and the request was handed off.
-    """
+    """With a valid Bearer, the request reaches FastMCP. Anything other than 401
+    confirms auth passed and the request was handed off to the sub-app."""
     fake_key = MagicMock()
     fake_key.user_id = 7
     fake_key.scope = "write"
     app = create_app()
+    initialize_body = json.dumps({
+        "jsonrpc": "2.0", "id": 1, "method": "initialize",
+        "params": {
+            "protocolVersion": "2024-11-05",
+            "capabilities": {},
+            "clientInfo": {"name": "test", "version": "0"},
+        },
+    }).encode()
     with patch(
         "fabledassistant.mcp.auth.lookup_key",
         AsyncMock(return_value=fake_key),
     ):
-        async with app.test_client() as client:
-            resp = await client.post(
-                "/mcp",
-                json={
-                    "jsonrpc": "2.0",
-                    "id": 1,
-                    "method": "initialize",
-                    "params": {
-                        "protocolVersion": "2024-11-05",
-                        "capabilities": {},
-                        "clientInfo": {"name": "test", "version": "0"},
-                    },
-                },
-                headers={
-                    "Authorization": "Bearer fmcp_valid",
-                    "Accept": "application/json, text/event-stream",
-                },
-            )
-    assert resp.status_code != 401
+        status, _ = await _send_request(
+            app, "POST", "/mcp",
+            headers={
+                "Authorization": "Bearer fmcp_valid",
+                "Content-Type": "application/json",
+                "Accept": "application/json, text/event-stream",
+            },
+            body=initialize_body,
+        )
+    assert status != 401
 
 
 @pytest.mark.asyncio
 async def test_non_mcp_paths_bypass_mcp_dispatch():
-    """A non-/mcp path must not be routed to the FastMCP sub-app. Hitting an
-    unknown /api/* route should return 404 from Quart, not 401 from the MCP
-    middleware."""
+    """A non-/mcp path must reach Quart's normal routing, not the MCP dispatch."""
     app = create_app()
-    async with app.test_client() as client:
-        resp = await client.get("/api/this-route-does-not-exist")
-    assert resp.status_code != 401
+    status, _ = await _send_request(app, "GET", "/api/this-route-does-not-exist")
+    assert status != 401