fix(tests): use call_args instead of capturing kwargs in multiagent tests

- Replace custom capture_kwargs functions with direct mock verification using call_args
- Use existing mock setup from create_mock_agent/create_mock_multi_agent instead of overriding with AsyncMock
- Apply consistent pattern across all three kwargs passing tests
- Addresses reviewer feedback for cleaner test implementation

Fixes strands-agents#816

Author: aditya270520

tests/strands/multiagent/test_graph.py

@@ -1092,16 +1092,9 @@ async def test_state_reset_only_with_cycles_enabled():
 @pytest.mark.asyncio
 async def test_graph_kwargs_passing_agent(mock_strands_tracer, mock_use_span):
     """Test that kwargs are passed through to underlying Agent nodes."""
-    # Create a mock agent that captures kwargs
+    # Create a mock agent
     kwargs_agent = create_mock_agent("kwargs_agent", "Response with kwargs")
 
-    async def capture_kwargs(*args, **kwargs):
-        # Store kwargs for verification
-        capture_kwargs.captured_kwargs = kwargs
-        return kwargs_agent.return_value
-
-    kwargs_agent.invoke_async = MagicMock(side_effect=capture_kwargs)
-
     # Create graph
     builder = GraphBuilder()
     builder.add_node(kwargs_agent, "kwargs_node")
@@ -1111,28 +1104,19 @@ async def capture_kwargs(*args, **kwargs):
     test_kwargs = {"custom_param": "test_value", "another_param": 42}
     result = await graph.invoke_async("Test kwargs passing", **test_kwargs)
 
-    # Verify kwargs were passed to agent
-    assert hasattr(capture_kwargs, "captured_kwargs")
-    assert capture_kwargs.captured_kwargs == test_kwargs
+    # Verify kwargs were passed to agent using call_args
+    kwargs_agent.invoke_async.assert_called_once()
+    call_args, call_kwargs = kwargs_agent.invoke_async.call_args
+    assert call_kwargs == test_kwargs
     assert result.status == Status.COMPLETED
 
 
 @pytest.mark.asyncio
 async def test_graph_kwargs_passing_multiagent(mock_strands_tracer, mock_use_span):
     """Test that kwargs are passed through to underlying MultiAgentBase nodes."""
-    # Create a mock MultiAgentBase that captures kwargs
+    # Create a mock MultiAgentBase
     kwargs_multiagent = create_mock_multi_agent("kwargs_multiagent", "MultiAgent response with kwargs")
 
-    # Store the original return value
-    original_result = kwargs_multiagent.invoke_async.return_value
-
-    async def capture_kwargs(*args, **kwargs):
-        # Store kwargs for verification
-        capture_kwargs.captured_kwargs = kwargs
-        return original_result
-
-    kwargs_multiagent.invoke_async = AsyncMock(side_effect=capture_kwargs)
-
     # Create graph
     builder = GraphBuilder()
     builder.add_node(kwargs_multiagent, "multiagent_node")
@@ -1142,24 +1126,18 @@ async def capture_kwargs(*args, **kwargs):
     test_kwargs = {"custom_param": "test_value", "another_param": 42}
     result = await graph.invoke_async("Test kwargs passing to multiagent", **test_kwargs)
 
-    # Verify kwargs were passed to multiagent
-    assert hasattr(capture_kwargs, "captured_kwargs")
-    assert capture_kwargs.captured_kwargs == test_kwargs
+    # Verify kwargs were passed to multiagent using call_args
+    kwargs_multiagent.invoke_async.assert_called_once()
+    call_args, call_kwargs = kwargs_multiagent.invoke_async.call_args
+    assert call_kwargs == test_kwargs
     assert result.status == Status.COMPLETED
 
 
 def test_graph_kwargs_passing_sync(mock_strands_tracer, mock_use_span):
     """Test that kwargs are passed through to underlying nodes in sync execution."""
-    # Create a mock agent that captures kwargs
+    # Create a mock agent
     kwargs_agent = create_mock_agent("kwargs_agent", "Response with kwargs")
 
-    async def capture_kwargs(*args, **kwargs):
-        # Store kwargs for verification
-        capture_kwargs.captured_kwargs = kwargs
-        return kwargs_agent.return_value
-
-    kwargs_agent.invoke_async = MagicMock(side_effect=capture_kwargs)
-
     # Create graph
     builder = GraphBuilder()
     builder.add_node(kwargs_agent, "kwargs_node")
@@ -1169,7 +1147,8 @@ async def capture_kwargs(*args, **kwargs):
     test_kwargs = {"custom_param": "test_value", "another_param": 42}
     result = graph("Test kwargs passing sync", **test_kwargs)
 
-    # Verify kwargs were passed to agent
-    assert hasattr(capture_kwargs, "captured_kwargs")
-    assert capture_kwargs.captured_kwargs == test_kwargs
+    # Verify kwargs were passed to agent using call_args
+    kwargs_agent.invoke_async.assert_called_once()
+    call_args, call_kwargs = kwargs_agent.invoke_async.call_args
+    assert call_kwargs == test_kwargs
     assert result.status == Status.COMPLETED