[Core] Validate PipelineConfig in __post_init__ (#6829)

Signed-off-by: Alex Brooks <albrooks@redhat.com>

tests/model_executor/models/minicpmo_4_5/test_pipeline.py

@@ -26,6 +26,7 @@ from vllm_omni.config.pipeline_registry import OMNI_PIPELINES
 from vllm_omni.config.stage_config import (
     PipelineConfig,
     StageExecutionType,
+    StagePipelineConfig,
     _apply_platform_overrides,
     load_deploy_config,
     merge_pipeline_deploy,
@@ -65,7 +66,9 @@ class TestRegistryDeclaration:
         assert not hasattr(pipeline, "max_native_duplex_sessions")
 
     def test_ordinary_pipeline_defaults_to_no_duplex_control(self) -> None:
-        pipeline = PipelineConfig(model_type="ordinary")
+        pipeline = PipelineConfig(
+            model_type="ordinary", stages=(StagePipelineConfig(stage_id=0, model_stage="a", final_output=True),)
+        )
         assert pipeline.duplex_control_enabled is False
         assert pipeline.duplex_serving_adapter is None
         assert not hasattr(pipeline, "max_native_duplex_sessions")
@@ -80,10 +83,6 @@ class TestPipelineTopology:
         assert len(pipeline.stages) == 3
         assert [s.stage_id for s in pipeline.stages] == [0, 1, 2]
 
-    def test_topology_validates(self, pipeline: PipelineConfig) -> None:
-        # ``validate`` returns a list of structural errors; empty == valid.
-        assert pipeline.validate() == []
-
     def test_thinker_stage(self, pipeline: PipelineConfig) -> None:
         thinker = pipeline.get_stage(0)
         assert thinker is not None

tests/model_executor/models/test_nemotron_voicechat_registration.py

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """L1 registration + config-shim tests for NemotronVoiceChat (CPU, no weights)."""
 
 import subprocess
@@ -59,7 +59,6 @@ def test_pipeline_registered_with_three_stages() -> None:
     assert code2wav.execution_type == StageExecutionType.LLM_GENERATION
     assert code2wav.final_output and code2wav.final_output_type == "audio"
     assert code2wav.input_sources == (1,)
-    assert pipeline.validate() == []
 
 
 def test_architectures_registered() -> None: