Fix-swarm-handoff (#4198)

* fix select speaker for swarm

* Fix max-turn = 1 for swarm

python/packages/autogen-agentchat/tests/test_group_chat.py

@@ -791,3 +791,27 @@ async def test_swarm_handoff_using_tool_calls(monkeypatch: pytest.MonkeyPatch) -
         else:
             assert message == result.messages[index]
         index += 1
+
+
+@pytest.mark.asyncio
+async def test_swarm_pause_and_resume() -> None:
+    first_agent = _HandOffAgent("first_agent", description="first agent", next_agent="second_agent")
+    second_agent = _HandOffAgent("second_agent", description="second agent", next_agent="third_agent")
+    third_agent = _HandOffAgent("third_agent", description="third agent", next_agent="first_agent")
+
+    team = Swarm([second_agent, first_agent, third_agent], max_turns=1)
+    result = await team.run(task="task")
+    assert len(result.messages) == 2
+    assert result.messages[0].content == "task"
+    assert result.messages[1].content == "Transferred to third_agent."
+
+    # Resume with a new task.
+    result = await team.run(task="new task")
+    assert len(result.messages) == 2
+    assert result.messages[0].content == "new task"
+    assert result.messages[1].content == "Transferred to first_agent."
+
+    # Resume with the same task.
+    result = await team.run()
+    assert len(result.messages) == 1
+    assert result.messages[0].content == "Transferred to second_agent."