test(processor): all processors use now the same create_transition (#1906)

* test(processor): all processors use now the same create_transition

* test(processor): use identity instead of lambda for transition in pipelines

tests/processor/test_batch_processor.py

@@ -28,21 +28,7 @@ from lerobot.processor import (
     ProcessorStepRegistry,
     TransitionKey,
 )
-
-
-def create_transition(
-    observation=None, action=None, reward=None, done=None, truncated=None, info=None, complementary_data=None
-):
-    """Helper to create an EnvTransition dictionary."""
-    return {
-        TransitionKey.OBSERVATION: observation,
-        TransitionKey.ACTION: action,
-        TransitionKey.REWARD: reward,
-        TransitionKey.DONE: done,
-        TransitionKey.TRUNCATED: truncated,
-        TransitionKey.INFO: info,
-        TransitionKey.COMPLEMENTARY_DATA: complementary_data,
-    }
+from lerobot.processor.converters import create_transition, identity_transition
 
 
 def test_state_1d_to_2d():
@@ -248,7 +234,9 @@ def test_mixed_observation():
 def test_integration_with_robot_processor():
     """Test AddBatchDimensionProcessorStep integration with RobotProcessor."""
     to_batch_processor = AddBatchDimensionProcessorStep()
-    pipeline = DataProcessorPipeline([to_batch_processor], to_transition=lambda x: x, to_output=lambda x: x)
+    pipeline = DataProcessorPipeline(
+        [to_batch_processor], to_transition=identity_transition, to_output=identity_transition
+    )
 
     # Create unbatched observation
     observation = {
@@ -289,7 +277,7 @@ def test_save_and_load_pretrained():
     """Test saving and loading AddBatchDimensionProcessorStep with RobotProcessor."""
     processor = AddBatchDimensionProcessorStep()
     pipeline = DataProcessorPipeline(
-        [processor], name="BatchPipeline", to_transition=lambda x: x, to_output=lambda x: x
+        [processor], name="BatchPipeline", to_transition=identity_transition, to_output=identity_transition
     )
 
     with tempfile.TemporaryDirectory() as tmp_dir:
@@ -302,7 +290,7 @@ def test_save_and_load_pretrained():
 
         # Load pipeline
         loaded_pipeline = DataProcessorPipeline.from_pretrained(
-            tmp_dir, to_transition=lambda x: x, to_output=lambda x: x
+            tmp_dir, to_transition=identity_transition, to_output=identity_transition
         )
 
         assert loaded_pipeline.name == "BatchPipeline"
@@ -330,12 +318,14 @@ def test_registry_functionality():
 def test_registry_based_save_load():
     """Test saving and loading using registry name."""
     processor = AddBatchDimensionProcessorStep()
-    pipeline = DataProcessorPipeline([processor], to_transition=lambda x: x, to_output=lambda x: x)
+    pipeline = DataProcessorPipeline(
+        [processor], to_transition=identity_transition, to_output=identity_transition
+    )
 
     with tempfile.TemporaryDirectory() as tmp_dir:
         pipeline.save_pretrained(tmp_dir)
         loaded_pipeline = DataProcessorPipeline.from_pretrained(
-            tmp_dir, to_transition=lambda x: x, to_output=lambda x: x
+            tmp_dir, to_transition=identity_transition, to_output=identity_transition
         )
 
         # Verify the loaded processor works
@@ -703,7 +693,7 @@ def test_complementary_data_none():
     transition = create_transition(complementary_data=None)
     result = processor(transition)
 
-    assert result[TransitionKey.COMPLEMENTARY_DATA] is None
+    assert result[TransitionKey.COMPLEMENTARY_DATA] == {}
 
 
 def test_complementary_data_empty():