[Diffusion] Prepare HunyuanImage3 for Scheduler-managed paged KV cache (#5541)

Signed-off-by: zwhzzz0821 <zwhzzz0821@users.noreply.github.com>
Co-authored-by: zwhzzz0821 <zwhzzz0821@users.noreply.github.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

tests/diffusion/diffusion_kv/test_config.py

@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import pytest
+
+from vllm_omni.diffusion.data import OmniDiffusionConfig
+from vllm_omni.diffusion.diffusion_kv.config import DiffusionKVCacheMode
+
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
+
+
+@pytest.fixture(autouse=True)
+def _fixed_master_port(monkeypatch) -> None:
+    monkeypatch.setattr(OmniDiffusionConfig, "_resolve_master_port", lambda _self: 29500)
+
+
+def test_dense_legacy_is_default() -> None:
+    config = OmniDiffusionConfig.from_kwargs()
+
+    assert config.diffusion_kv_mode is DiffusionKVCacheMode.DENSE_LEGACY
+
+
+def test_paged_worker_local_is_rejected_until_implemented() -> None:
+    with pytest.raises(ValueError, match="reserved but not implemented"):
+        OmniDiffusionConfig.from_kwargs(diffusion_kv_mode="paged_worker_local")
+
+
+def test_unknown_cache_mode_is_rejected() -> None:
+    with pytest.raises(ValueError, match="Unsupported Diffusion KV diffusion_kv_mode"):
+        OmniDiffusionConfig.from_kwargs(diffusion_kv_mode="unknown")
+
+
+def test_non_mapping_omni_kv_config_is_rejected() -> None:
+    with pytest.raises(TypeError, match="omni_kv_config must be a mapping"):
+        OmniDiffusionConfig.from_kwargs(omni_kv_config="paged_scheduler")
+
+
+def test_paged_scheduler_rejects_dense_legacy_kv_receive() -> None:
+    with pytest.raises(ValueError, match="does not support imported AR KV"):
+        OmniDiffusionConfig.from_kwargs(
+            diffusion_kv_mode="paged_scheduler",
+            omni_kv_config={"need_recv_cache": True},
+        )
+
+
+def test_paged_scheduler_does_not_depend_on_model_registry() -> None:
+    config = OmniDiffusionConfig.from_kwargs(
+        model_class_name="FutureDiffusionModel",
+        diffusion_kv_mode="paged_scheduler",
+    )
+
+    assert config.diffusion_kv_mode is DiffusionKVCacheMode.PAGED_SCHEDULER