Handle sync command service handlers

src/core/interfaces/command_service.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import inspect
 from collections.abc import Awaitable, Callable
 from typing import Any
 
@@ -24,7 +25,18 @@ def __init__(self, handler: CommandServiceHandler):
     async def process_commands(
         self, messages: list[Any], session_id: str
     ) -> ProcessedResult:
-        return await self._handler(messages, session_id)
+        result = self._handler(messages, session_id)
+
+        if inspect.isawaitable(result):
+            return await result
+
+        if isinstance(result, ProcessedResult):
+            return result
+
+        raise TypeError(
+            "The command service handler must return a ProcessedResult or an awaitable"
+            " resolving to ProcessedResult."
+        )
 
 
 def ensure_command_service(

tests/unit/core/test_command_service_module.py

@@ -1,4 +1,5 @@
 import pytest
+
 from src.core.domain.processed_result import ProcessedResult
 from src.core.interfaces.command_service import ensure_command_service
 from src.core.interfaces.command_service_interface import ICommandService
@@ -48,6 +49,23 @@ async def handler(messages: list[str], session_id: str) -> ProcessedResult:
     assert result.command_results == ["session"]
 
 
+@pytest.mark.asyncio
+async def test_ensure_command_service_wraps_sync_callable() -> None:
+    def handler(messages: list[str], session_id: str) -> ProcessedResult:
+        return ProcessedResult(
+            modified_messages=[value.upper() for value in messages],
+            command_executed=True,
+            command_results=[session_id],
+        )
+
+    validated_service = ensure_command_service(handler)
+
+    result = await validated_service.process_commands(["hello"], "session")
+    assert result.modified_messages == ["HELLO"]
+    assert result.command_executed is True
+    assert result.command_results == ["session"]
+
+
 def test_ensure_command_service_rejects_none() -> None:
     with pytest.raises(ValueError) as exc:
         ensure_command_service(None)