From 674595836248569cf56fe3c25011df25fffff71f Mon Sep 17 00:00:00 2001
From: Steven Palma <imstevenpmwork@ieee.org>
Date: Wed, 10 Sep 2025 18:45:47 +0200
Subject: [PATCH] fix(processor): specialized processors respect contract by
 raising if none (#1909)

* fix(processor): specialized processor now raise

* test(processor): fix tests for now raise specialized processors

* test(processor): use identity in newly introduced pipeline
---
 src/lerobot/processor/pipeline.py             |  14 +--
 tests/processor/test_batch_processor.py       | 116 +++++++++---------
 tests/processor/test_diffusion_processor.py   |   6 +-
 tests/processor/test_observation_processor.py |   2 +-
 tests/processor/test_rename_processor.py      |   2 +-
 tests/processor/test_sac_processor.py         |   2 +-
 tests/processor/test_tokenizer_processor.py   |  10 +-
 7 files changed, 78 insertions(+), 74 deletions(-)

diff --git a/src/lerobot/processor/pipeline.py b/src/lerobot/processor/pipeline.py
index 274bc1e72..9afff7e48 100644
--- a/src/lerobot/processor/pipeline.py
+++ b/src/lerobot/processor/pipeline.py
@@ -829,7 +829,7 @@ class ObservationProcessorStep(ProcessorStep, ABC):
 
         observation = new_transition.get(TransitionKey.OBSERVATION)
         if observation is None:
-            return new_transition
+            raise ValueError("ObservationProcessorStep requires an observation in the transition.")
 
         processed_observation = self.observation(observation)
         new_transition[TransitionKey.OBSERVATION] = processed_observation
@@ -876,7 +876,7 @@ class ActionProcessorStep(ProcessorStep, ABC):
 
         action = new_transition.get(TransitionKey.ACTION)
         if action is None:
-            return new_transition
+            raise ValueError("ActionProcessorStep requires an action in the transition.")
 
         processed_action = self.action(action)
         new_transition[TransitionKey.ACTION] = processed_action
@@ -922,7 +922,7 @@ class RewardProcessorStep(ProcessorStep, ABC):
 
         reward = new_transition.get(TransitionKey.REWARD)
         if reward is None:
-            return new_transition
+            raise ValueError("RewardProcessorStep requires a reward in the transition.")
 
         processed_reward = self.reward(reward)
         new_transition[TransitionKey.REWARD] = processed_reward
@@ -973,7 +973,7 @@ class DoneProcessorStep(ProcessorStep, ABC):
 
         done = new_transition.get(TransitionKey.DONE)
         if done is None:
-            return new_transition
+            raise ValueError("DoneProcessorStep requires a done flag in the transition.")
 
         processed_done = self.done(done)
         new_transition[TransitionKey.DONE] = processed_done
@@ -1020,7 +1020,7 @@ class TruncatedProcessorStep(ProcessorStep, ABC):
 
         truncated = new_transition.get(TransitionKey.TRUNCATED)
         if truncated is None:
-            return new_transition
+            raise ValueError("TruncatedProcessorStep requires a truncated flag in the transition.")
 
         processed_truncated = self.truncated(truncated)
         new_transition[TransitionKey.TRUNCATED] = processed_truncated
@@ -1072,7 +1072,7 @@ class InfoProcessorStep(ProcessorStep, ABC):
 
         info = new_transition.get(TransitionKey.INFO)
         if info is None:
-            return new_transition
+            raise ValueError("InfoProcessorStep requires an info dictionary in the transition.")
 
         processed_info = self.info(info)
         new_transition[TransitionKey.INFO] = processed_info
@@ -1105,7 +1105,7 @@ class ComplementaryDataProcessorStep(ProcessorStep, ABC):
 
         complementary_data = new_transition.get(TransitionKey.COMPLEMENTARY_DATA)
         if complementary_data is None:
-            return new_transition
+            raise ValueError("ComplementaryDataProcessorStep requires complementary data in the transition.")
 
         processed_complementary_data = self.complementary_data(complementary_data)
         new_transition[TransitionKey.COMPLEMENTARY_DATA] = processed_complementary_data
diff --git a/tests/processor/test_batch_processor.py b/tests/processor/test_batch_processor.py
index 1258a29d2..100c9648c 100644
--- a/tests/processor/test_batch_processor.py
+++ b/tests/processor/test_batch_processor.py
@@ -38,7 +38,7 @@ def test_state_1d_to_2d():
     # Test observation.state
     state_1d = torch.randn(7)
     observation = {OBS_STATE: state_1d}
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -54,7 +54,7 @@ def test_env_state_1d_to_2d():
     # Test observation.environment_state
     env_state_1d = torch.randn(10)
     observation = {OBS_ENV_STATE: env_state_1d}
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -70,7 +70,7 @@ def test_image_3d_to_4d():
     # Test observation.image
     image_3d = torch.randn(224, 224, 3)
     observation = {OBS_IMAGE: image_3d}
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -90,7 +90,7 @@ def test_multiple_images_3d_to_4d():
         f"{OBS_IMAGES}.camera1": image1_3d,
         f"{OBS_IMAGES}.camera2": image2_3d,
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -118,7 +118,7 @@ def test_already_batched_tensors_unchanged():
         OBS_ENV_STATE: env_state_2d,
         OBS_IMAGE: image_4d,
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -142,7 +142,7 @@ def test_higher_dimensional_tensors_unchanged():
         OBS_STATE: state_3d,
         OBS_IMAGE: image_5d,
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -163,7 +163,7 @@ def test_non_tensor_values_unchanged():
         "custom_key": 42,  # Integer
         "another_key": {"nested": "dict"},  # Dict
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -180,10 +180,10 @@ def test_none_observation():
     """Test processor handles None observation gracefully."""
     processor = AddBatchDimensionProcessorStep()
 
-    transition = create_transition(observation=None)
+    transition = create_transition(observation={}, action={})
     result = processor(transition)
 
-    assert result[TransitionKey.OBSERVATION] is None
+    assert result[TransitionKey.OBSERVATION] == {}
 
 
 def test_empty_observation():
@@ -191,7 +191,7 @@ def test_empty_observation():
     processor = AddBatchDimensionProcessorStep()
 
     observation = {}
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
 
@@ -216,7 +216,7 @@ def test_mixed_observation():
         "other_tensor": other_tensor,
         "non_tensor": "string_value",
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
     processed_obs = result[TransitionKey.OBSERVATION]
@@ -243,7 +243,7 @@ def test_integration_with_robot_processor():
         OBS_STATE: torch.randn(7),
         OBS_IMAGE: torch.randn(224, 224, 3),
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = pipeline(transition)
     processed_obs = result[TransitionKey.OBSERVATION]
@@ -299,7 +299,7 @@ def test_save_and_load_pretrained():
 
         # Test functionality of loaded processor
         observation = {OBS_STATE: torch.randn(5)}
-        transition = create_transition(observation=observation)
+        transition = create_transition(observation=observation, action={})
 
         result = loaded_pipeline(transition)
         assert result[TransitionKey.OBSERVATION][OBS_STATE].shape == (1, 5)
@@ -333,7 +333,7 @@ def test_registry_based_save_load():
             OBS_STATE: torch.randn(3),
             OBS_IMAGE: torch.randn(100, 100, 3),
         }
-        transition = create_transition(observation=observation)
+        transition = create_transition(observation=observation, action={})
 
         result = loaded_pipeline(transition)
         processed_obs = result[TransitionKey.OBSERVATION]
@@ -355,7 +355,7 @@ def test_device_compatibility():
         OBS_STATE: state_1d,
         OBS_IMAGE: image_3d,
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
     processed_obs = result[TransitionKey.OBSERVATION]
@@ -415,7 +415,7 @@ def test_edge_case_zero_dimensional_tensors():
         OBS_STATE: scalar_tensor,
         "scalar_value": scalar_tensor,
     }
-    transition = create_transition(observation=observation)
+    transition = create_transition(observation=observation, action={})
 
     result = processor(transition)
     processed_obs = result[TransitionKey.OBSERVATION]
@@ -432,7 +432,7 @@ def test_action_1d_to_2d():
 
     # Create 1D action tensor
     action_1d = torch.randn(4)
-    transition = create_transition(action=action_1d)
+    transition = create_transition(observation={}, action=action_1d)
 
     result = processor(transition)
 
@@ -450,12 +450,12 @@ def test_action_already_batched():
     action_batched_5 = torch.randn(5, 4)
 
     # Single batch
-    transition = create_transition(action=action_batched_1)
+    transition = create_transition(action=action_batched_1, observation={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.ACTION], action_batched_1)
 
     # Multiple batch
-    transition = create_transition(action=action_batched_5)
+    transition = create_transition(action=action_batched_5, observation={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.ACTION], action_batched_5)
 
@@ -466,13 +466,13 @@ def test_action_higher_dimensional():
 
     # 3D action tensor (e.g., sequence of actions)
     action_3d = torch.randn(2, 4, 3)
-    transition = create_transition(action=action_3d)
+    transition = create_transition(action=action_3d, observation={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.ACTION], action_3d)
 
     # 4D action tensor
     action_4d = torch.randn(2, 10, 4, 3)
-    transition = create_transition(action=action_4d)
+    transition = create_transition(action=action_4d, observation={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.ACTION], action_4d)
 
@@ -482,7 +482,7 @@ def test_action_scalar_tensor():
     processor = AddBatchDimensionProcessorStep()
 
     action_scalar = torch.tensor(1.5)
-    transition = create_transition(action=action_scalar)
+    transition = create_transition(action=action_scalar, observation={})
     result = processor(transition)
 
     # Should remain scalar
@@ -496,25 +496,25 @@ def test_action_non_tensor():
 
     # List action
     action_list = [0.1, 0.2, 0.3, 0.4]
-    transition = create_transition(action=action_list)
+    transition = create_transition(action=action_list, observation={})
     result = processor(transition)
     assert result[TransitionKey.ACTION] == action_list
 
     # Numpy array action (as Python object, not converted)
     action_numpy = np.array([1, 2, 3, 4])
-    transition = create_transition(action=action_numpy)
+    transition = create_transition(action=action_numpy, observation={})
     result = processor(transition)
     assert np.array_equal(result[TransitionKey.ACTION], action_numpy)
 
     # String action (edge case)
     action_string = "forward"
-    transition = create_transition(action=action_string)
+    transition = create_transition(action=action_string, observation={})
     result = processor(transition)
     assert result[TransitionKey.ACTION] == action_string
 
     # Dict action (structured action)
     action_dict = {"linear": [0.5, 0.0], "angular": 0.2}
-    transition = create_transition(action=action_dict)
+    transition = create_transition(action=action_dict, observation={})
     result = processor(transition)
     assert result[TransitionKey.ACTION] == action_dict
 
@@ -523,9 +523,9 @@ def test_action_none():
     """Test that None action is handled correctly."""
     processor = AddBatchDimensionProcessorStep()
 
-    transition = create_transition(action=None)
+    transition = create_transition(action={}, observation={})
     result = processor(transition)
-    assert result[TransitionKey.ACTION] is None
+    assert result[TransitionKey.ACTION] == {}
 
 
 def test_action_with_observation():
@@ -557,7 +557,7 @@ def test_action_different_sizes():
 
     for size in action_sizes:
         action = torch.randn(size)
-        transition = create_transition(action=action)
+        transition = create_transition(action=action, observation={})
         result = processor(transition)
 
         assert result[TransitionKey.ACTION].shape == (1, size)
@@ -571,7 +571,7 @@ def test_action_device_compatibility():
 
     # CUDA action
     action_cuda = torch.randn(4, device="cuda")
-    transition = create_transition(action=action_cuda)
+    transition = create_transition(action=action_cuda, observation={})
     result = processor(transition)
 
     assert result[TransitionKey.ACTION].shape == (1, 4)
@@ -579,7 +579,7 @@ def test_action_device_compatibility():
 
     # CPU action
     action_cpu = torch.randn(4, device="cpu")
-    transition = create_transition(action=action_cpu)
+    transition = create_transition(action=action_cpu, observation={})
     result = processor(transition)
 
     assert result[TransitionKey.ACTION].shape == (1, 4)
@@ -595,7 +595,7 @@ def test_action_dtype_preservation():
 
     for dtype in dtypes:
         action = torch.randn(4).to(dtype)
-        transition = create_transition(action=action)
+        transition = create_transition(action=action, observation={})
         result = processor(transition)
 
         assert result[TransitionKey.ACTION].dtype == dtype
@@ -608,7 +608,7 @@ def test_empty_action_tensor():
 
     # Empty 1D tensor
     action_empty = torch.tensor([])
-    transition = create_transition(action=action_empty)
+    transition = create_transition(action=action_empty, observation={})
     result = processor(transition)
 
     # Should add batch dimension even to empty tensor
@@ -616,7 +616,7 @@ def test_empty_action_tensor():
 
     # Empty 2D tensor (already batched)
     action_empty_2d = torch.randn(1, 0)
-    transition = create_transition(action=action_empty_2d)
+    transition = create_transition(action=action_empty_2d, observation={})
     result = processor(transition)
 
     # Should remain unchanged
@@ -630,7 +630,7 @@ def test_task_string_to_list():
 
     # Create complementary data with string task
     complementary_data = {"task": "pick_cube"}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(action={}, observation={}, complementary_data=complementary_data)
 
     result = processor(transition)
 
@@ -647,14 +647,14 @@ def test_task_string_validation():
 
     # Valid string task - should be converted to list
     complementary_data = {"task": "valid_task"}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
     result = processor(transition)
     processed_comp_data = result[TransitionKey.COMPLEMENTARY_DATA]
     assert processed_comp_data["task"] == ["valid_task"]
 
     # Valid list of strings - should remain unchanged
     complementary_data = {"task": ["task1", "task2"]}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
     result = processor(transition)
     processed_comp_data = result[TransitionKey.COMPLEMENTARY_DATA]
     assert processed_comp_data["task"] == ["task1", "task2"]
@@ -676,7 +676,7 @@ def test_task_list_of_strings():
 
     for task_list in test_lists:
         complementary_data = {"task": task_list}
-        transition = create_transition(complementary_data=complementary_data)
+        transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
         result = processor(transition)
 
@@ -690,7 +690,7 @@ def test_complementary_data_none():
     """Test processor handles None complementary_data gracefully."""
     processor = AddBatchDimensionProcessorStep()
 
-    transition = create_transition(complementary_data=None)
+    transition = create_transition(complementary_data=None, action={}, observation={})
     result = processor(transition)
 
     assert result[TransitionKey.COMPLEMENTARY_DATA] == {}
@@ -701,7 +701,7 @@ def test_complementary_data_empty():
     processor = AddBatchDimensionProcessorStep()
 
     complementary_data = {}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -717,7 +717,7 @@ def test_complementary_data_no_task():
         "timestamp": 1234567890.0,
         "extra_info": "some data",
     }
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -736,7 +736,7 @@ def test_complementary_data_mixed():
         "difficulty": "hard",
         "metadata": {"scene": "kitchen"},
     }
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -803,7 +803,7 @@ def test_task_comprehensive_string_cases():
     # Test that all string tasks get properly batched
     for task in string_tasks:
         complementary_data = {"task": task}
-        transition = create_transition(complementary_data=complementary_data)
+        transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
         result = processor(transition)
 
@@ -825,7 +825,7 @@ def test_task_comprehensive_string_cases():
 
     for task_list in list_tasks:
         complementary_data = {"task": task_list}
-        transition = create_transition(complementary_data=complementary_data)
+        transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
         result = processor(transition)
 
@@ -845,7 +845,7 @@ def test_task_preserves_other_keys():
         "config": {"speed": "slow", "precision": "high"},
         "metrics": [1.0, 2.0, 3.0],
     }
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -869,7 +869,7 @@ def test_index_scalar_to_1d():
     # Create 0D index tensor (scalar)
     index_0d = torch.tensor(42, dtype=torch.int64)
     complementary_data = {"index": index_0d}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -886,7 +886,7 @@ def test_task_index_scalar_to_1d():
     # Create 0D task_index tensor (scalar)
     task_index_0d = torch.tensor(7, dtype=torch.int64)
     complementary_data = {"task_index": task_index_0d}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -908,7 +908,7 @@ def test_index_and_task_index_together():
         "task_index": task_index_0d,
         "task": "pick_object",
     }
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -936,13 +936,13 @@ def test_index_already_batched():
 
     # Test 1D (already batched)
     complementary_data = {"index": index_1d}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.COMPLEMENTARY_DATA]["index"], index_1d)
 
     # Test 2D
     complementary_data = {"index": index_2d}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.COMPLEMENTARY_DATA]["index"], index_2d)
 
@@ -957,13 +957,13 @@ def test_task_index_already_batched():
 
     # Test 1D (already batched)
     complementary_data = {"task_index": task_index_1d}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.COMPLEMENTARY_DATA]["task_index"], task_index_1d)
 
     # Test 2D
     complementary_data = {"task_index": task_index_2d}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
     result = processor(transition)
     assert torch.equal(result[TransitionKey.COMPLEMENTARY_DATA]["task_index"], task_index_2d)
 
@@ -976,7 +976,7 @@ def test_index_non_tensor_unchanged():
         "index": 42,  # Plain int, not tensor
         "task_index": [1, 2, 3],  # List, not tensor
     }
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -999,7 +999,7 @@ def test_index_dtype_preservation():
             "index": index_0d,
             "task_index": task_index_0d,
         }
-        transition = create_transition(complementary_data=complementary_data)
+        transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
         result = processor(transition)
 
@@ -1062,7 +1062,7 @@ def test_index_device_compatibility():
         "index": index_0d,
         "task_index": task_index_0d,
     }
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
     processed_comp_data = result[TransitionKey.COMPLEMENTARY_DATA]
@@ -1081,7 +1081,7 @@ def test_empty_index_tensor():
     # Empty 0D tensor doesn't make sense, but test empty 1D
     index_empty = torch.tensor([], dtype=torch.int64)
     complementary_data = {"index": index_empty}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     result = processor(transition)
 
@@ -1094,7 +1094,7 @@ def test_action_processing_creates_new_transition():
     processor = AddBatchDimensionProcessorStep()
 
     action = torch.randn(4)
-    transition = create_transition(action=action)
+    transition = create_transition(action=action, observation={})
 
     # Store reference to original transition
     original_transition = transition
@@ -1116,7 +1116,7 @@ def test_task_processing_creates_new_transition():
     processor = AddBatchDimensionProcessorStep()
 
     complementary_data = {"task": "sort_objects"}
-    transition = create_transition(complementary_data=complementary_data)
+    transition = create_transition(complementary_data=complementary_data, observation={}, action={})
 
     # Store reference to original transition and complementary_data
     original_transition = transition
diff --git a/tests/processor/test_diffusion_processor.py b/tests/processor/test_diffusion_processor.py
index 5163997a7..98215dc18 100644
--- a/tests/processor/test_diffusion_processor.py
+++ b/tests/processor/test_diffusion_processor.py
@@ -218,7 +218,11 @@ def test_diffusion_processor_without_stats():
     """Test Diffusion processor creation without dataset statistics."""
     config = create_default_config()
 
-    preprocessor, postprocessor = make_diffusion_pre_post_processors(config, dataset_stats=None)
+    preprocessor, postprocessor = make_diffusion_pre_post_processors(
+        config,
+        dataset_stats=None,
+        preprocessor_kwargs={"to_transition": identity_transition, "to_output": identity_transition},
+    )
 
     # Should still create processors
     assert preprocessor is not None
diff --git a/tests/processor/test_observation_processor.py b/tests/processor/test_observation_processor.py
index f21c9f662..57f32482d 100644
--- a/tests/processor/test_observation_processor.py
+++ b/tests/processor/test_observation_processor.py
@@ -136,7 +136,7 @@ def test_none_observation():
     """Test processor with None observation."""
     processor = VanillaObservationProcessorStep()
 
-    transition = create_transition()
+    transition = create_transition(observation={})
     result = processor(transition)
 
     assert result == transition
diff --git a/tests/processor/test_rename_processor.py b/tests/processor/test_rename_processor.py
index 54b47f8c8..1baab4cdc 100644
--- a/tests/processor/test_rename_processor.py
+++ b/tests/processor/test_rename_processor.py
@@ -86,7 +86,7 @@ def test_none_observation():
     """Test processor with None observation."""
     processor = RenameObservationsProcessorStep(rename_map={"old": "new"})
 
-    transition = create_transition()
+    transition = create_transition(observation={})
     result = processor(transition)
 
     # Should return transition unchanged
diff --git a/tests/processor/test_sac_processor.py b/tests/processor/test_sac_processor.py
index fb18c1d06..5e26b5c8f 100644
--- a/tests/processor/test_sac_processor.py
+++ b/tests/processor/test_sac_processor.py
@@ -372,7 +372,7 @@ def test_sac_processor_edge_cases():
     assert processed[TransitionKey.ACTION].shape == (1, 5)
 
     # Test with None action
-    transition = create_transition(observation={OBS_STATE: torch.randn(10)}, action=None)
+    transition = create_transition(observation={OBS_STATE: torch.randn(10)}, action={})
     processed = preprocessor(transition)
     assert processed[TransitionKey.OBSERVATION][OBS_STATE].shape == (1, 10)
     # When action is None, it may still be present with None value
diff --git a/tests/processor/test_tokenizer_processor.py b/tests/processor/test_tokenizer_processor.py
index 8c2a2d834..70f4fe4e0 100644
--- a/tests/processor/test_tokenizer_processor.py
+++ b/tests/processor/test_tokenizer_processor.py
@@ -203,7 +203,7 @@ def test_none_complementary_data(mock_auto_tokenizer):
 
     processor = TokenizerProcessorStep(tokenizer_name="test-tokenizer")
 
-    transition = create_transition(complementary_data=None)
+    transition = create_transition(observation={}, complementary_data=None)
 
     result = processor(transition)
     assert result == transition  # Should return unchanged
@@ -218,7 +218,7 @@ def test_missing_task_key(mock_auto_tokenizer):
 
     processor = TokenizerProcessorStep(tokenizer_name="test-tokenizer")
 
-    transition = create_transition(complementary_data={"other_field": "some value"})
+    transition = create_transition(observation={}, complementary_data={"other_field": "some value"})
 
     result = processor(transition)
     assert result == transition  # Should return unchanged
@@ -233,7 +233,7 @@ def test_none_task_value(mock_auto_tokenizer):
 
     processor = TokenizerProcessorStep(tokenizer_name="test-tokenizer")
 
-    transition = create_transition(complementary_data={"task": None})
+    transition = create_transition(observation={}, complementary_data={"task": None})
 
     result = processor(transition)
     assert result == transition  # Should return unchanged
@@ -249,13 +249,13 @@ def test_unsupported_task_type(mock_auto_tokenizer):
     processor = TokenizerProcessorStep(tokenizer_name="test-tokenizer")
 
     # Test with integer task
-    transition = create_transition(complementary_data={"task": 123})
+    transition = create_transition(observation={}, complementary_data={"task": 123})
 
     result = processor(transition)
     assert result == transition  # Should return unchanged
 
     # Test with mixed list
-    transition = create_transition(complementary_data={"task": ["text", 123, "more text"]})
+    transition = create_transition(observation={}, complementary_data={"task": ["text", 123, "more text"]})
 
     result = processor(transition)
     assert result == transition  # Should return unchanged