fix(testing): update webhook type-check for typed McpWebhookPayload return

create_mcp_webhook_payload was changed in #632 to return McpWebhookPayload
(typed Pydantic model) instead of dict[str, Any]. The type-check test
still demonstrated the dict + cast() pattern, which no longer typechecks.

Update to demonstrate the new zero-ignore adopter pattern: typed
attribute access (payload.task_id) for reads, to_wire_dict(payload) for
HTTP serialization. Use TaskType.create_media_buy (a real async task
type — get_products is sync-only and not in the TaskType enum).

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

Author: bokelley

tests/type_checks/webhook_payload_construction.py

@@ -1,39 +1,44 @@
-"""Adopter pattern: create_mcp_webhook_payload usage with cast() for field access.
+"""Adopter pattern: create_mcp_webhook_payload usage with typed attribute access.
 
-create_mcp_webhook_payload returns dict[str, Any]. The zero-ignore pattern
-for extracting typed values is cast() — explicit, visible, and does not
-require # type: ignore.
+create_mcp_webhook_payload returns a typed McpWebhookPayload Pydantic model.
+The zero-ignore adopter pattern is direct attribute access for typed reads
+and to_wire_dict() for HTTP serialization — no cast() needed.
 """
+
 from __future__ import annotations
 
 import json
-from typing import Any, cast
+from typing import Any
 
-from adcp.types import GeneratedTaskStatus
-from adcp.webhooks import create_mcp_webhook_payload
+from adcp.types import GeneratedTaskStatus, McpWebhookPayload, TaskType
+from adcp.webhooks import create_mcp_webhook_payload, to_wire_dict
 
 
-def build_completed_payload(task_id: str, products: list[dict[str, Any]]) -> dict[str, Any]:
+def build_completed_payload(task_id: str, media_buy_id: str) -> McpWebhookPayload:
     return create_mcp_webhook_payload(
         task_id=task_id,
-        task_type="get_products",
+        task_type=TaskType.create_media_buy,
         status=GeneratedTaskStatus.completed,
-        result={"products": products},
-        message=f"Found {len(products)} products",
+        result={"media_buy_id": media_buy_id, "status": "active"},
+        message=f"Media buy {media_buy_id} activated",
     )
 
 
-def extract_task_id(payload: dict[str, Any]) -> str:
-    return cast(str, payload["task_id"])
+def extract_task_id(payload: McpWebhookPayload) -> str:
+    return payload.task_id
+
+
+def extract_status(payload: McpWebhookPayload) -> str:
+    return payload.status
 
 
-def extract_status(payload: dict[str, Any]) -> str:
-    return cast(str, payload["status"])
+def serialize_for_http(payload: McpWebhookPayload) -> dict[str, Any]:
+    return to_wire_dict(payload)
 
 
-payload = build_completed_payload("task_123", [{"product_id": "p1"}])
+payload = build_completed_payload("task_123", "mb_abc")
 
-serialized = json.dumps(payload)
+serialized = json.dumps(serialize_for_http(payload))
 assert isinstance(serialized, str)
 
 task_id = extract_task_id(payload)