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_device_processor.py

@@ -20,28 +20,7 @@ import torch
 
 from lerobot.configs.types import FeatureType, PipelineFeatureType, PolicyFeature
 from lerobot.processor import DataProcessorPipeline, DeviceProcessorStep, TransitionKey
-
-
-def create_transition(
-    observation=None, action=None, reward=None, done=None, truncated=None, info=None, complementary_data=None
-):
-    """Helper function to create a transition dictionary."""
-    transition = {}
-    if observation is not None:
-        transition[TransitionKey.OBSERVATION] = observation
-    if action is not None:
-        transition[TransitionKey.ACTION] = action
-    if reward is not None:
-        transition[TransitionKey.REWARD] = reward
-    if done is not None:
-        transition[TransitionKey.DONE] = done
-    if truncated is not None:
-        transition[TransitionKey.TRUNCATED] = truncated
-    if info is not None:
-        transition[TransitionKey.INFO] = info
-    if complementary_data is not None:
-        transition[TransitionKey.COMPLEMENTARY_DATA] = complementary_data
-    return transition
+from lerobot.processor.converters import create_transition, identity_transition
 
 
 def test_basic_functionality():
@@ -147,14 +126,14 @@ def test_none_values():
     # Test with None observation
     transition = create_transition(observation=None, action=torch.randn(5))
     result = processor(transition)
-    assert TransitionKey.OBSERVATION not in result
+    assert result[TransitionKey.OBSERVATION] is None
     assert result[TransitionKey.ACTION].device.type == "cpu"
 
     # Test with None action
     transition = create_transition(observation={"observation.state": torch.randn(10)}, action=None)
     result = processor(transition)
     assert result[TransitionKey.OBSERVATION]["observation.state"].device.type == "cpu"
-    assert TransitionKey.ACTION not in result
+    assert result[TransitionKey.ACTION] is None
 
 
 def test_empty_observation():
@@ -315,8 +294,8 @@ def test_integration_with_robot_processor():
     processor = DataProcessorPipeline(
         steps=[batch_processor, device_processor],
         name="test_pipeline",
-        to_transition=lambda x: x,
-        to_output=lambda x: x,
+        to_transition=identity_transition,
+        to_output=identity_transition,
     )
 
     # Create test data
@@ -823,7 +802,7 @@ def test_complementary_data_none():
     result = processor(transition)
 
     # Complementary data should not be in the result (same as input)
-    assert TransitionKey.COMPLEMENTARY_DATA not in result
+    assert result[TransitionKey.COMPLEMENTARY_DATA] == {}
 
 
 @pytest.mark.skipif(not torch.cuda.is_available(), reason="CUDA not available")
@@ -995,8 +974,8 @@ def test_policy_processor_integration():
             DeviceProcessorStep(device="cuda"),
         ],
         name="test_preprocessor",
-        to_transition=lambda x: x,
-        to_output=lambda x: x,
+        to_transition=identity_transition,
+        to_output=identity_transition,
     )
 
     # Create output processor (postprocessor) that moves to CPU
@@ -1006,8 +985,8 @@ def test_policy_processor_integration():
             UnnormalizerProcessorStep(features={ACTION: features[ACTION]}, norm_map=norm_map, stats=stats),
         ],
         name="test_postprocessor",
-        to_transition=lambda x: x,
-        to_output=lambda x: x,
+        to_transition=identity_transition,
+        to_output=identity_transition,
     )
 
     # Test data on CPU