test/tools: catalog, grants, and async tool helpers

tests/test_tools/helpers.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 import inspect
 from typing import TYPE_CHECKING, Any, cast
 
@@ -8,8 +9,20 @@ if TYPE_CHECKING:
 
 
 def call_sync(definition: ToolDefinition, *args: object, **kwargs: object) -> str:
+    """Invoke a tool handler from a **sync** test.
+
+    Async handlers are run with ``asyncio.run``. Inside an already-running
+    event loop (async tests), use :func:`call_async` instead.
+    """
     result: Any = definition.handler(*args, **kwargs)
-    assert not inspect.isawaitable(result)
+    if inspect.isawaitable(result):
+        try:
+            asyncio.get_running_loop()
+        except RuntimeError:
+            result = asyncio.run(result)
+        else:
+            msg = "call_sync cannot await inside a running event loop; use call_async"
+            raise RuntimeError(msg)
     return cast("str", result)