add processor tests to multitask dit tests

tests/policies/multi_task_dit/test_multi_task_dit.py

@@ -24,9 +24,12 @@ import pytest
 import torch
 from torch import Tensor
 
-from lerobot.configs.types import FeatureType, PolicyFeature
+from lerobot.configs.types import FeatureType, NormalizationMode, PolicyFeature
 from lerobot.policies.multi_task_dit.configuration_multi_task_dit import MultiTaskDiTConfig
 from lerobot.policies.multi_task_dit.modeling_multi_task_dit import MultiTaskDiTPolicy
+from lerobot.policies.multi_task_dit.processor_multi_task_dit import (
+    make_multi_task_dit_pre_post_processors,
+)
 from lerobot.utils.constants import ACTION, OBS_IMAGES, OBS_STATE
 from lerobot.utils.random_utils import seeded_context, set_seed
 
@@ -147,6 +150,144 @@ def test_multi_task_dit_policy_forward(batch_size: int, state_dim: int, action_d
     loss.backward()
 
 
+def test_multi_task_dit_pre_post_processors():
+    """Test pre and post processors for Multi-Task DiT policy."""
+    state_dim = 10
+    action_dim = 8
+    n_obs_steps = 2
+    horizon = 16
+
+    config = create_config(
+        state_dim=state_dim,
+        action_dim=action_dim,
+        n_obs_steps=n_obs_steps,
+        horizon=horizon,
+        n_action_steps=8,
+    )
+    config.device = "cpu"
+
+    # Set normalization mode to match the stats we're providing
+    config.normalization_mapping = {
+        "VISUAL": NormalizationMode.IDENTITY,
+        "STATE": NormalizationMode.MEAN_STD,  # Use MEAN_STD since we provide mean/std stats
+        "ACTION": NormalizationMode.MIN_MAX,
+    }
+
+    # Create dataset stats for normalization
+    dataset_stats = {
+        "observation.state": {
+            "mean": torch.zeros(state_dim),
+            "std": torch.ones(state_dim),
+        },
+        "action": {
+            "min": torch.full((action_dim,), -1.0),
+            "max": torch.ones(action_dim),
+        },
+    }
+
+    # Create processors
+    preprocessor, postprocessor = make_multi_task_dit_pre_post_processors(
+        config=config, dataset_stats=dataset_stats
+    )
+
+    # Test preprocessor with sample data
+    batch = {
+        "observation.state": torch.randn(state_dim),
+        f"{OBS_IMAGES}.laptop": torch.rand(3, 224, 224),
+        ACTION: torch.randn(action_dim),
+        "task": "pick up the cube",
+    }
+
+    processed_batch = preprocessor(batch)
+
+    # Check that data is batched
+    assert processed_batch["observation.state"].shape == (1, state_dim)
+    assert processed_batch[f"{OBS_IMAGES}.laptop"].shape == (1, 3, 224, 224)
+    assert processed_batch[ACTION].shape == (1, action_dim)
+    assert "task" in processed_batch
+
+    # Check that data is on correct device
+    assert processed_batch["observation.state"].device.type == "cpu"
+    assert processed_batch[f"{OBS_IMAGES}.laptop"].device.type == "cpu"
+    assert processed_batch[ACTION].device.type == "cpu"
+
+    # Test postprocessor with sample action (PolicyAction is just a torch.Tensor)
+    action = torch.randn(1, action_dim)
+    processed_action = postprocessor(action)
+
+    # Check that action is unnormalized and on CPU
+    assert processed_action.shape == (1, action_dim)
+    assert processed_action.device.type == "cpu"
+
+
+def test_multi_task_dit_pre_post_processors_normalization():
+    """Test that normalization and unnormalization work correctly with simple sanity check numbers."""
+    state_dim = 3
+    action_dim = 2
+
+    config = create_config(
+        state_dim=state_dim,
+        action_dim=action_dim,
+        n_obs_steps=2,
+        horizon=16,
+        n_action_steps=8,
+    )
+    config.device = "cpu"
+
+    # Set normalization mode to match the stats we're providing
+    config.normalization_mapping = {
+        "VISUAL": NormalizationMode.IDENTITY,
+        "STATE": NormalizationMode.MEAN_STD,  # Use MEAN_STD since we provide mean/std stats
+        "ACTION": NormalizationMode.MIN_MAX,
+    }
+
+    # Use simple stats that will actually transform the values
+    dataset_stats = {
+        "observation.state": {
+            "mean": torch.full((state_dim,), 5.0),
+            "std": torch.full((state_dim,), 2.0),
+        },
+        "action": {
+            "min": torch.zeros(action_dim),
+            "max": torch.full((action_dim,), 2.0),
+        },
+    }
+
+    # Create processors
+    preprocessor, postprocessor = make_multi_task_dit_pre_post_processors(
+        config=config, dataset_stats=dataset_stats
+    )
+
+    # Use simple input values
+    input_state = torch.tensor([7.0, 5.0, 3.0])  # Will normalize to [1.0, 0.0, -1.0]
+    input_action = torch.tensor([1.0, 2.0])  # Will normalize to [0.0, 1.0]
+
+    batch = {
+        "observation.state": input_state,
+        f"{OBS_IMAGES}.laptop": torch.rand(3, 224, 224),
+        ACTION: input_action,
+        "task": "test task",
+    }
+
+    # Process through preprocessor
+    processed_batch = preprocessor(batch)
+
+    # State normalization: (x - mean) / std
+    expected_normalized_state = torch.tensor([1.0, 0.0, -1.0])
+    assert torch.allclose(processed_batch["observation.state"][0], expected_normalized_state, atol=1e-5)
+
+    # Action normalization: (x - min) / (max - min) * 2 - 1
+    expected_normalized_action = torch.tensor([0.0, 1.0])
+    assert torch.allclose(processed_batch[ACTION][0], expected_normalized_action, atol=1e-5)
+
+    # Test unnormalization: should recover original values
+    normalized_action_tensor = processed_batch[ACTION][0:1]  # Keep batch dimension
+    unnormalized_action = postprocessor(normalized_action_tensor)
+
+    # Should recover original action values
+    assert torch.allclose(unnormalized_action[0], input_action, atol=1e-4)
+
+
 @pytest.mark.parametrize("batch_size,state_dim,action_dim", [(2, 10, 10), (1, 6, 6)])
 def test_multi_task_dit_policy_select_action(batch_size: int, state_dim: int, action_dim: int):
     """Test select_action (inference mode)."""
@@ -166,10 +307,22 @@ def test_multi_task_dit_policy_select_action(batch_size: int, state_dim: int, ac
     policy.eval()
     policy.reset()  # Reset queues before inference
 
+    # Create processors - use IDENTITY normalization when no stats provided
+    config.normalization_mapping = {
+        "VISUAL": NormalizationMode.IDENTITY,
+        "STATE": NormalizationMode.IDENTITY,
+        "ACTION": NormalizationMode.IDENTITY,
+    }
+    preprocessor, postprocessor = make_multi_task_dit_pre_post_processors(config=config, dataset_stats=None)
+
     with torch.no_grad():
         observation_batch = create_observation_batch(batch_size=batch_size, state_dim=state_dim)
-        selected_action = policy.select_action(observation_batch)
-        assert selected_action.shape == (batch_size, action_dim)
+        # Process observation through preprocessor
+        processed_obs = preprocessor(observation_batch)
+        selected_action = policy.select_action(processed_obs)
+        # Process action through postprocessor (PolicyAction is just a torch.Tensor)
+        processed_action = postprocessor(selected_action)
+        assert processed_action.shape == (batch_size, action_dim)
 
 
 def test_multi_task_dit_policy_diffusion_objective():
@@ -222,10 +375,21 @@ def test_multi_task_dit_policy_diffusion_objective():
 
     # Test inference
     policy.eval()
+    # Use IDENTITY normalization when no stats provided
+    config.normalization_mapping = {
+        "VISUAL": NormalizationMode.IDENTITY,
+        "STATE": NormalizationMode.IDENTITY,
+        "ACTION": NormalizationMode.IDENTITY,
+    }
+    preprocessor, postprocessor = make_multi_task_dit_pre_post_processors(config=config, dataset_stats=None)
     with torch.no_grad():
         observation_batch = create_observation_batch(batch_size=batch_size, state_dim=state_dim)
-        selected_action = policy.select_action(observation_batch)
-        assert selected_action.shape == (batch_size, action_dim)
+        # Process observation through preprocessor
+        processed_obs = preprocessor(observation_batch)
+        selected_action = policy.select_action(processed_obs)
+        # Process action through postprocessor (PolicyAction is just a torch.Tensor)
+        processed_action = postprocessor(selected_action)
+        assert processed_action.shape == (batch_size, action_dim)
 
 
 def test_multi_task_dit_policy_flow_matching_objective():
@@ -278,10 +442,21 @@ def test_multi_task_dit_policy_flow_matching_objective():
 
     # Test inference
     policy.eval()
+    # Use IDENTITY normalization when no stats provided
+    config.normalization_mapping = {
+        "VISUAL": NormalizationMode.IDENTITY,
+        "STATE": NormalizationMode.IDENTITY,
+        "ACTION": NormalizationMode.IDENTITY,
+    }
+    preprocessor, postprocessor = make_multi_task_dit_pre_post_processors(config=config, dataset_stats=None)
     with torch.no_grad():
         observation_batch = create_observation_batch(batch_size=batch_size, state_dim=state_dim)
-        selected_action = policy.select_action(observation_batch)
-        assert selected_action.shape == (batch_size, action_dim)
+        # Process observation through preprocessor
+        processed_obs = preprocessor(observation_batch)
+        selected_action = policy.select_action(processed_obs)
+        # Process action through postprocessor (PolicyAction is just a torch.Tensor)
+        processed_action = postprocessor(selected_action)
+        assert processed_action.shape == (batch_size, action_dim)
 
 
 def test_multi_task_dit_policy_save_and_load(tmp_path):