Apply ruff formatting

Author: angangwa

python/semantic_kernel/agents/orchestration/group_chat.py

@@ -289,7 +289,7 @@ def __init__(
         """
         self._manager = manager
         self._internal_topic_type = internal_topic_type
-        self._chat_history = chat_history or ChatHistory()
+        self._chat_history = chat_history if chat_history is not None else ChatHistory()
         self._participant_descriptions = participant_descriptions
         self._result_callback = result_callback
 

python/tests/unit/agents/orchestration/test_group_chat_with_reducers.py

@@ -0,0 +1,139 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+import sys
+
+from semantic_kernel.agents.orchestration.group_chat import (
+    GroupChatOrchestration,
+    RoundRobinGroupChatManager,
+)
+from semantic_kernel.agents.runtime.in_process.in_process_runtime import InProcessRuntime
+from semantic_kernel.contents.chat_history import ChatHistory
+from semantic_kernel.contents.history_reducer.chat_history_truncation_reducer import ChatHistoryTruncationReducer
+from tests.unit.agents.orchestration.conftest import MockAgent
+
+if sys.version_info >= (3, 12):
+    pass  # pragma: no cover
+else:
+    pass  # pragma: no cover
+
+
+# region Tests with ChatHistoryTruncationReducer
+
+
+async def test_group_chat_with_chat_history_parameter():
+    """Test GroupChatOrchestration accepts chat_history parameter."""
+    agent = MockAgent(name="TestAgent", description="Test agent")
+    chat_history = ChatHistory()
+
+    # Should not raise an error
+    orchestration = GroupChatOrchestration(
+        members=[agent], manager=RoundRobinGroupChatManager(), chat_history=chat_history
+    )
+
+    assert orchestration._chat_history is chat_history
+
+
+async def test_group_chat_with_truncation_reducer():
+    """Test GroupChatOrchestration with ChatHistoryTruncationReducer."""
+    agent = MockAgent(name="TestAgent", description="Test agent")
+
+    # Create truncation reducer that keeps only 2 messages
+    reducer = ChatHistoryTruncationReducer(target_count=2, threshold_count=0, auto_reduce=True)
+
+    runtime = InProcessRuntime()
+    runtime.start()
+
+    try:
+        orchestration = GroupChatOrchestration(
+            members=[agent], manager=RoundRobinGroupChatManager(max_rounds=3), chat_history=reducer
+        )
+
+        orchestration_result = await orchestration.invoke(task="Test message", runtime=runtime)
+        await orchestration_result.get(timeout=1.0)
+
+        # Verify the reducer was used and has messages
+        assert len(reducer.messages) > 0, "Reducer should have received messages"
+
+        # Verify truncation is working - should not exceed target_count + threshold_count + buffer
+        # (The exact count may vary due to "transfer" messages and timing)
+        assert len(reducer.messages) <= 5, "Reducer should limit message count"
+
+    finally:
+        await runtime.stop_when_idle()
+
+
+async def test_group_chat_fallback_to_regular_chat_history():
+    """Test that GroupChat falls back to add_message for regular ChatHistory."""
+    agent = MockAgent(name="TestAgent", description="Test agent")
+
+    # Use regular ChatHistory (no add_message_async method)
+    regular_history = ChatHistory()
+
+    runtime = InProcessRuntime()
+    runtime.start()
+
+    try:
+        # Should work without errors
+        orchestration = GroupChatOrchestration(
+            members=[agent], manager=RoundRobinGroupChatManager(max_rounds=1), chat_history=regular_history
+        )
+
+        orchestration_result = await orchestration.invoke(task="Test message", runtime=runtime)
+        await orchestration_result.get(timeout=1.0)
+
+        # Verify messages were added to history
+        assert len(regular_history.messages) > 0, "Messages should be added to regular ChatHistory"
+
+    finally:
+        await runtime.stop_when_idle()
+
+
+async def test_group_chat_no_chat_history_parameter():
+    """Test GroupChatOrchestration works when no chat_history provided."""
+    agent = MockAgent(name="TestAgent", description="Test agent")
+
+    orchestration = GroupChatOrchestration(members=[agent], manager=RoundRobinGroupChatManager())
+
+    # Should not set chat_history in constructor when None provided
+    assert orchestration._chat_history is None
+
+
+async def test_empty_reducer_not_replaced_by_default_history():
+    """Test that empty ChatHistoryReducer instances are not replaced by default ChatHistory.
+
+    This is a regression test for the bug where empty reducers evaluated to False
+    and were replaced by ChatHistory() due to the 'chat_history or ChatHistory()' pattern.
+    """
+    agent = MockAgent(name="TestAgent", description="Test agent")
+
+    # Create empty reducer (should evaluate to False in boolean context but still be used)
+    empty_reducer = ChatHistoryTruncationReducer(target_count=5, threshold_count=0, auto_reduce=True)
+
+    # Verify it's empty and evaluates to False initially
+    assert len(empty_reducer.messages) == 0
+    assert bool(empty_reducer) is False
+
+    runtime = InProcessRuntime()
+    runtime.start()
+
+    try:
+        orchestration = GroupChatOrchestration(
+            members=[agent], manager=RoundRobinGroupChatManager(max_rounds=1), chat_history=empty_reducer
+        )
+
+        orchestration_result = await orchestration.invoke(task="Test message", runtime=runtime)
+        await orchestration_result.get(timeout=1.0)
+
+        # Verify messages were added to our reducer (not a default ChatHistory)
+        assert len(empty_reducer.messages) > 0, "Messages should be added to the reducer instance"
+
+        # Verify we can access reducer-specific functionality (proves it's our reducer)
+        assert hasattr(empty_reducer, "auto_reduce"), "Should still be our reducer instance"
+        assert empty_reducer.auto_reduce is True, "Should have reducer-specific properties"
+        assert empty_reducer.target_count == 5, "Should have our original target_count"
+
+    finally:
+        await runtime.stop_when_idle()
+
+
+# endregion Tests with ChatHistoryTruncationReducer