test(core): Replace pytest.fail with functional assertions in token_usage and agent_capabilities

tests/test_token_usage.py

@@ -1,6 +1,9 @@
 import pytest
 import sys
 import os
+import hashlib
+from unittest.mock import patch, MagicMock
+from types import SimpleNamespace
 
 # Ensure project root is in path
 sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
@@ -9,6 +12,54 @@ import ai_client
 
 def test_token_usage_tracking() -> None:
  ai_client.reset_session()
- # Mock an API response with token usage
- # This would test the internal accumulator in ai_client
- pytest.fail("TODO: Implement assertions")
+ ai_client.clear_comms_log()
+ ai_client.set_provider("gemini", "gemini-2.0-flash")
+ 
+ # Mock credentials so we don't need a real file
+ with patch("ai_client._load_credentials") as mock_creds:
+  mock_creds.return_value = {"gemini": {"api_key": "fake-key"}}
+  
+  mock_resp = MagicMock()
+  # Use SimpleNamespace to ensure attributes are real values, not Mocks
+  mock_resp.usage_metadata = SimpleNamespace(
+   prompt_token_count=100,
+   candidates_token_count=50,
+   cached_content_token_count=20
+  )
+  
+  # Setup candidates
+  mock_candidate = MagicMock()
+  # Use spec to ensure hasattr(p, "function_call") is False for text parts
+  mock_part = MagicMock(spec=["text"])
+  mock_part.text = "Hello"
+  mock_candidate.content.parts = [mock_part]
+  mock_candidate.finish_reason.name = "STOP"
+  mock_resp.candidates = [mock_candidate]
+  
+  mock_chat = MagicMock()
+  mock_chat.send_message.return_value = mock_resp
+  mock_chat._history = []
+  
+  # Mock the client creation and storage
+  with patch("google.genai.Client") as mock_client_class:
+   mock_client_instance = mock_client_class.return_value
+   # Mock count_tokens to avoid call during send_gemini
+   mock_client_instance.models.count_tokens.return_value = MagicMock(total_tokens=100)
+   # Mock chats.create to return our mock_chat
+   mock_client_instance.chats.create.return_value = mock_chat
+   
+   ai_client._gemini_client = mock_client_instance
+   ai_client._gemini_chat = mock_chat
+   # Set the hash to prevent chat reset
+   ai_client._gemini_cache_md_hash = hashlib.md5("context".encode()).hexdigest()
+   
+   ai_client.send("context", "hi", enable_tools=False)
+ 
+ log = ai_client.get_comms_log()
+ # The log might have 'request' and 'response' entries
+ response_entries = [e for e in log if e["kind"] == "response"]
+ assert len(response_entries) > 0
+ usage = response_entries[0]["payload"]["usage"]
+ assert usage["input_tokens"] == 100
+ assert usage["output_tokens"] == 50
+ assert usage["cache_read_input_tokens"] == 20