feat(ai_client): Emit API lifecycle and tool execution events

tests/test_api_events.py

@@ -18,3 +18,97 @@ def test_event_emission():
     ai_client.events.emit("request_start", payload={"model": "test"})
     
     mock_callback.assert_called_once_with(payload={"model": "test"})
+
+def test_send_emits_events():
+    from unittest.mock import patch, MagicMock
+    
+    # We need to mock _ensure_gemini_client and the chat object it creates
+    with patch("ai_client._ensure_gemini_client"), \
+         patch("ai_client._gemini_client") as mock_client, \
+         patch("ai_client._gemini_chat") as mock_chat:
+        
+        # Setup mock response
+        mock_response = MagicMock()
+        mock_response.candidates = []
+        # Explicitly set usage_metadata as a mock with integer values
+        mock_usage = MagicMock()
+        mock_usage.prompt_token_count = 10
+        mock_usage.candidates_token_count = 5
+        mock_usage.cached_content_token_count = None
+        mock_response.usage_metadata = mock_usage
+        mock_chat.send_message.return_value = mock_response
+        mock_client.chats.create.return_value = mock_chat
+        
+        ai_client.set_provider("gemini", "gemini-flash")
+        
+        start_callback = MagicMock()
+        response_callback = MagicMock()
+        
+        ai_client.events.on("request_start", start_callback)
+        ai_client.events.on("response_received", response_callback)
+        
+        # We need to bypass the context changed check or set it up
+        ai_client.send("context", "message")
+        
+        assert start_callback.called
+        assert response_callback.called
+        
+        # Check payload
+        args, kwargs = start_callback.call_args
+        assert kwargs['payload']['provider'] == 'gemini'
+        
+def test_send_emits_tool_events():
+    from unittest.mock import patch, MagicMock
+    
+    with patch("ai_client._ensure_gemini_client"), \
+         patch("ai_client._gemini_client") as mock_client, \
+         patch("ai_client._gemini_chat") as mock_chat, \
+         patch("mcp_client.dispatch") as mock_dispatch:
+        
+        # 1. Setup mock response with a tool call
+        mock_fc = MagicMock()
+        mock_fc.name = "read_file"
+        mock_fc.args = {"path": "test.txt"}
+        
+        mock_response_with_tool = MagicMock()
+        mock_response_with_tool.candidates = [MagicMock()]
+        mock_part = MagicMock()
+        mock_part.text = "tool call text"
+        mock_part.function_call = mock_fc
+        mock_response_with_tool.candidates[0].content.parts = [mock_part]
+        mock_response_with_tool.candidates[0].finish_reason.name = "STOP"
+        
+        # Setup mock usage
+        mock_usage = MagicMock()
+        mock_usage.prompt_token_count = 10
+        mock_usage.candidates_token_count = 5
+        mock_usage.cached_content_token_count = None
+        mock_response_with_tool.usage_metadata = mock_usage
+        
+        # 2. Setup second mock response (final answer)
+        mock_response_final = MagicMock()
+        mock_response_final.candidates = []
+        mock_response_final.usage_metadata = mock_usage
+        
+        mock_chat.send_message.side_effect = [mock_response_with_tool, mock_response_final]
+        mock_dispatch.return_value = "file content"
+        
+        ai_client.set_provider("gemini", "gemini-flash")
+        
+        tool_callback = MagicMock()
+        ai_client.events.on("tool_execution", tool_callback)
+        
+        ai_client.send("context", "message")
+        
+        # Should be called twice: once for 'started', once for 'completed'
+        assert tool_callback.call_count == 2
+        
+        # Check 'started' call
+        args, kwargs = tool_callback.call_args_list[0]
+        assert kwargs['payload']['status'] == 'started'
+        assert kwargs['payload']['tool'] == 'read_file'
+        
+        # Check 'completed' call
+        args, kwargs = tool_callback.call_args_list[1]
+        assert kwargs['payload']['status'] == 'completed'
+        assert kwargs['payload']['result'] == 'file content'