[Feat][Config] Support additional_config for diffusion worker (#3020)

Signed-off-by: KexiongYu <yukexiong1@huawei.com>
Signed-off-by: Y. Fisher <yukexiong1@huawei.com>

tests/diffusion/test_diffusion_worker.py

@@ -14,7 +14,11 @@ import pytest
 import torch
 from pytest_mock import MockerFixture
 
-from vllm_omni.diffusion.worker.diffusion_worker import DiffusionWorker, _make_diffusion_vllm_model_config
+from vllm_omni.diffusion.worker.diffusion_worker import (
+    DiffusionWorker,
+    _create_diffusion_worker_vllm_config,
+    _make_diffusion_vllm_model_config,
+)
 
 pytestmark = [pytest.mark.core_model, pytest.mark.diffusion, pytest.mark.gpu]
 
@@ -348,4 +352,50 @@ class TestDiffusionWorkerWakeUp:
         # buffer2 should NOT be restored since it wasn't saved
         mock_buffer2.data.copy_.assert_not_called()
 
-        assert bool(result) is True
+        assert result is True
+
+
+class TestWorkerVllmConfigAdditionalConfig:
+    """Test worker-side VllmConfig construction with additional_config."""
+
+    def test_create_diffusion_worker_vllm_config_passes_additional_config(self, mocker: MockerFixture):
+        mock_vllm_config = mocker.Mock()
+        mock_vllm_cls = mocker.patch(
+            "vllm_omni.diffusion.worker.diffusion_worker.VllmConfig",
+            return_value=mock_vllm_config,
+        )
+        od_config = mocker.Mock(additional_config={"torchair_graph_config": {"enabled": True}})
+
+        result = _create_diffusion_worker_vllm_config(torch.device("cpu"), od_config)
+
+        assert result is mock_vllm_config
+        assert mock_vllm_cls.call_args.kwargs["additional_config"] == od_config.additional_config
+
+    def test_create_diffusion_worker_vllm_config_falls_back_when_constructor_rejects_additional_config(
+        self, mocker: MockerFixture
+    ):
+        mock_vllm_config = mocker.Mock()
+        mock_vllm_cls = mocker.patch(
+            "vllm_omni.diffusion.worker.diffusion_worker.VllmConfig",
+            side_effect=[
+                TypeError("VllmConfig.__init__() got an unexpected keyword argument 'additional_config'"),
+                mock_vllm_config,
+            ],
+        )
+        od_config = mocker.Mock(additional_config={"ascend_scheduler_config": {"foo": "bar"}})
+
+        result = _create_diffusion_worker_vllm_config(torch.device("cpu"), od_config)
+
+        assert result is mock_vllm_config
+        assert mock_vllm_cls.call_count == 2
+        assert getattr(mock_vllm_config, "additional_config") == od_config.additional_config
+
+    def test_create_diffusion_worker_vllm_config_reraises_other_type_errors(self, mocker: MockerFixture):
+        mocker.patch(
+            "vllm_omni.diffusion.worker.diffusion_worker.VllmConfig",
+            side_effect=TypeError("additional_config values must be hashable"),
+        )
+        od_config = mocker.Mock(additional_config={"ascend_scheduler_config": {"foo": "bar"}})
+
+        with pytest.raises(TypeError, match="hashable"):
+            _create_diffusion_worker_vllm_config(torch.device("cpu"), od_config)