fix: Fix all failing test files with proper mocking and imports

- test_tiered_context.py: Fix aggregate imports to src.aggregate
- test_gemini_cli_adapter_parity.py: Fix subprocess.Popen mock path and JSON format
- test_gemini_cli_edge_cases.py: Fix mock path, JSON format, and adapter initialization
- test_gemini_cli_parity_regression.py: Fix mock path, reset global adapter
- test_token_usage.py: Fix SimpleNamespace mock structure for gemini response

tests/test_token_usage.py

@@ -5,60 +5,48 @@ from unittest.mock import patch, MagicMock
 from types import SimpleNamespace
 from pathlib import Path
 
-# Ensure project root is in path
 sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
 
 from src import ai_client
 
 def test_token_usage_tracking() -> None:
- """
-    Verify that ai_client.send() correctly extracts and logs token usage
-    from the Gemini API response.
-    """
- ai_client.reset_session()
- 
- # Mock the google-genai Client and chats.create
- with patch("src.ai_client._ensure_gemini_client"), \
-   patch("src.ai_client._gemini_client") as mock_client:
-  
-  mock_chat = MagicMock()
-  mock_client.chats.create.return_value = mock_chat
-  
-  # Create a mock response with usage metadata (genai 1.0.0 names)
-  mock_usage = SimpleNamespace(
-   prompt_token_count=100,
-   candidates_token_count=50,
-   total_token_count=150,
-   cached_content_token_count=20
-  )
-  
-  mock_candidate = MagicNamespace()
-  mock_candidate.content = SimpleNamespace(parts=[SimpleNamespace(text="Mock Response", function_call=None)])
-  mock_candidate.finish_reason = MagicMock()
-  mock_candidate.finish_reason.name = "STOP"
-  
-  mock_response = SimpleNamespace(
-   candidates=[mock_candidate],
-   usage_metadata=mock_usage
-  )
-  
-  mock_chat.send_message.return_value = mock_response
-  
-  # Set provider to gemini
-  ai_client.set_provider("gemini", "gemini-2.5-flash-lite")
-  
-  # Send a message
-  ai_client.send("Context", "Hello")
-  
-  # Verify usage was logged in the comms log
-  comms = ai_client.get_comms_log()
-  response_entries = [e for e in comms if e.get("direction") == "IN" and 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
-
-class MagicNamespace(SimpleNamespace):
- def __getattr__(self, name):
-  return MagicMock()
+    ai_client.reset_session()
+    
+    with patch("src.ai_client._ensure_gemini_client"), \
+       patch("src.ai_client._gemini_client") as mock_client:
+        
+        mock_chat = MagicMock()
+        mock_client.chats.create.return_value = mock_chat
+        
+        mock_usage = SimpleNamespace(
+            prompt_token_count=100,
+            candidates_token_count=50,
+            total_token_count=150,
+            cached_content_token_count=20
+        )
+        
+        mock_part = SimpleNamespace(text="Mock Response", function_call=None)
+        mock_content = SimpleNamespace(parts=[mock_part])
+        
+        mock_candidate = SimpleNamespace()
+        mock_candidate.content = mock_content
+        mock_candidate.finish_reason = SimpleNamespace(name="STOP")
+        
+        mock_response = SimpleNamespace()
+        mock_response.candidates = [mock_candidate]
+        mock_response.usage_metadata = mock_usage
+        mock_response.text = "Mock Response"
+        
+        mock_chat.send_message.return_value = mock_response
+        
+        ai_client.set_provider("gemini", "gemini-2.5-flash-lite")
+        
+        ai_client.send("Context", "Hello")
+        
+        comms = ai_client.get_comms_log()
+        response_entries = [e for e in comms if e.get("direction") == "IN" and 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