test(backend): update unit tests for LLM monitoring changes

- Fixed MockLLMClient to accept step_name parameter

- Updated test mocks for OpenAI SDK structure

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/app/test/test_phase1_llm_client.py

@@ -20,34 +20,31 @@ class TestLLMClient:
     @pytest.mark.asyncio
     async def test_llm_call_success(self, monkeypatch):
         """Should return content from mocked LLM API."""
+        from unittest.mock import MagicMock, AsyncMock
         settings = get_settings()
         client = LLMClient(settings)
 
-        # Mock the underlying HTTP response
+        mock_message = MagicMock()
-        class _Resp:
+        mock_message.content = "mock response"
-            status_code = 200
+        mock_choice = MagicMock()
-            def json(self):
+        mock_choice.message = mock_message
-                return {
+        mock_usage = MagicMock()
-                    "choices": [{"message": {"content": "mock response"}}]
+        mock_usage.prompt_tokens = 10
-                }
+        mock_usage.completion_tokens = 5
-            def raise_for_status(self):
+        mock_response = MagicMock()
-                pass
+        mock_response.choices = [mock_choice]
+        mock_response.usage = mock_usage
 
-        async def _mock_post(*args, **kwargs):  # type: ignore
+        client._client.chat.completions.create = AsyncMock(return_value=mock_response)
-            return _Resp()
 
-        # Patch AsyncClient.post
+        result = await client.complete(prompt="test prompt", temperature=0.7, step_name="TestStep")
-        if hasattr(client, "_client") and client._client is not None:
-            client._client.post = _mock_post  # type: ignore
-        result = await client.complete(prompt="test prompt", temperature=0.7)
         assert isinstance(result, str)
         assert "mock" in result
 
     def test_llm_provider_switching(self):
         settings = get_settings()
-        # Ensure base URL comes from settings via client; the client stores base_url
         client = LLMClient(settings)
-        assert settings.llm_base_url.rstrip("/") in client.base_url
+        assert str(client._client.base_url).rstrip("/") == settings.llm_base_url.rstrip("/")
 
     @pytest.mark.asyncio
     async def test_llm_api_error_handling(self, monkeypatch):

backend/app/test/test_phase1_query_decomposer.py

@@ -12,9 +12,11 @@ class MockLLMClient:
     def __init__(self, response: str):
         self._response = response
         self.last_prompt = None
+        self.last_step_name = None
 
-    async def complete(self, prompt: str, temperature: float = 0.7) -> str:
+    async def complete(self, prompt: str, temperature: float = 0.7, step_name: str = "LLM") -> str:
         self.last_prompt = prompt
+        self.last_step_name = step_name
         return self._response