fix: update swarm_agent to handle agent lookup and add relevant unit …

…tests

autogen/agentchat/contrib/swarm_agent.py

@@ -127,6 +127,12 @@ def swarm_transition(last_speaker: SwarmAgent, groupchat: GroupChat):
             if isinstance(next_agent, str):
                 next_agent = groupchat.agent_by_name(name=next_agent)
 
+                # If no agent is found, raise an error or handle it appropriately
+                if next_agent is None:
+                    raise ValueError(
+                        f"No agent found with the name '{next_agent}'. Ensure the agent exists in the group chat."
+                    )
+
             return next_agent
 
         # get the last swarm agent

test/agentchat/contrib/test_swarm.py

@@ -1,10 +1,13 @@
 # Copyright (c) 2023 - 2024, Owners of https://github.com/ag2ai
 #
 # SPDX-License-Identifier: Apache-2.0
+import os
+import pprint
 from typing import Any, Dict
 from unittest.mock import MagicMock, patch
 
 import pytest
+from dotenv import load_dotenv
 
 from autogen.agentchat.contrib.swarm_agent import (
     __CONTEXT_VARIABLES_PARAM_NAME__,
@@ -461,5 +464,67 @@ def test_initialization():
         )
 
 
+def test_string_agent_params_for_transfer():
+    """Test that string agent parameters are handled correctly."""
+
+    # Load environment variables
+    load_dotenv()
+
+    # Fetch OpenAI API key from the environment
+    openai_api_key = os.environ.get("OPENAI_API_KEY")
+    if not openai_api_key:
+        raise ValueError("OPENAI_API_KEY is not set in the environment variables.")
+
+    # Initialize context variables
+    context_variables = {}
+
+    # Define test messages
+    messages = [
+        {
+            "role": "user",
+            "content": "Begin by calling the hello_world() function.",
+        }
+    ]
+
+    # Define a simple function for testing
+    def hello_world(context_variables: dict) -> SwarmResult:
+        value = "Hello, World!"
+        return SwarmResult(values=value, context_variables=context_variables, agent="agent_2")
+
+    # Define LLM configuration
+    llm_config = {
+        "cache_seed": 42,
+        "model": "gpt-4o-2024-08-06",
+        "api_key": openai_api_key,
+    }
+
+    # Create SwarmAgent instances
+    agent_1 = SwarmAgent(
+        name="agent_1",
+        system_message="Your task is to call hello_world() function.",
+        llm_config=llm_config,
+        functions=[hello_world],
+    )
+
+    agent_2 = SwarmAgent(
+        name="agent_2",
+        system_message="Your task is to let the user know what the previous agent said.",
+        llm_config=llm_config,
+        functions=[],
+    )
+
+    # Initiate the swarm chat
+    chat_result, final_context, last_active_agent = initiate_swarm_chat(
+        initial_agent=agent_1,
+        agents=[agent_1, agent_2],
+        context_variables=context_variables,
+        messages=messages,
+        after_work=AFTER_WORK(AfterWorkOption.TERMINATE),
+    )
+
+    # Print the chat result for debugging or verification
+    # pprint.pprint(chat_result)
+
+
 if __name__ == "__main__":
     pytest.main([__file__])