fix leaking imports in minimal testing

tests/async_inference/test_e2e.py

@@ -35,8 +35,10 @@ from concurrent import futures
 import pytest
 import torch
 
-# Skip entire module if grpc is not available
+# Skip entire module if required deps are not available
 pytest.importorskip("grpc")
+pytest.importorskip("serial", reason="pyserial is required (install lerobot[hardware])")
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
 
 # -----------------------------------------------------------------------------
 # End-to-end test

tests/async_inference/test_robot_client.py

@@ -25,8 +25,10 @@ from queue import Queue
 import pytest
 import torch
 
-# Skip entire module if grpc is not available
+# Skip entire module if required deps are not available
 pytest.importorskip("grpc")
+pytest.importorskip("serial", reason="pyserial is required (install lerobot[hardware])")
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
 
 # -----------------------------------------------------------------------------
 # Test fixtures

tests/conftest.py

@@ -17,24 +17,39 @@
 import traceback
 
 import pytest
-from serial import SerialException
 
 from lerobot.configs.types import FeatureType, PipelineFeatureType, PolicyFeature
+from lerobot.utils.import_utils import is_package_available
 from tests.utils import DEVICE
 
-# Import fixture modules as plugins
+# Import fixture modules as plugins.
+# Fixtures that depend on optional packages are only registered when those packages are available,
+# so that tests can be collected and run even with a minimal install.
 pytest_plugins = [
-    "tests.fixtures.dataset_factories",
-    "tests.fixtures.files",
-    "tests.fixtures.hub",
     "tests.fixtures.optimizers",
 ]
 
+if is_package_available("datasets"):
+    pytest_plugins += [
+        "tests.fixtures.dataset_factories",
+        "tests.fixtures.files",
+        "tests.fixtures.hub",
+    ]
+
 
 def pytest_collection_finish():
     print(f"\nTesting with {DEVICE=}")
 
 
+def _is_serial_exception(exc: Exception) -> bool:
+    """Check if an exception is a SerialException without requiring pyserial."""
+    if not is_package_available("pyserial", import_name="serial"):
+        return False
+    from serial import SerialException
+
+    return isinstance(exc, SerialException)
+
+
 def _check_component_availability(component_type, available_components, make_component):
     """Generic helper to check if a hardware component is available"""
     if component_type not in available_components:
@@ -53,7 +68,7 @@ def _check_component_availability(component_type, available_components, make_com
 
         if isinstance(e, ModuleNotFoundError):
             print(f"\nInstall module '{e.name}'")
-        elif isinstance(e, SerialException):
+        elif _is_serial_exception(e):
             print("\nNo physical device detected.")
         elif isinstance(e, ValueError) and "camera_index" in str(e):
             print("\nNo physical camera detected.")

tests/datasets/test_aggregate.py

@@ -16,7 +16,11 @@
 
 from unittest.mock import patch
 
-import datasets
+import pytest
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
+import datasets  # noqa: E402
 import torch
 
 from lerobot.datasets.aggregate import aggregate_datasets

tests/datasets/test_compute_stats.py

@@ -18,6 +18,8 @@ from unittest.mock import patch
 import numpy as np
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.compute_stats import (
     RunningQuantileStats,
     _assert_type_and_shape,

tests/datasets/test_dataset_metadata.py

@@ -20,6 +20,8 @@ import json
 import numpy as np
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.dataset_metadata import LeRobotDatasetMetadata
 from lerobot.datasets.utils import INFO_PATH
 from tests.fixtures.constants import DEFAULT_FPS, DUMMY_ROBOT_TYPE

tests/datasets/test_dataset_reader.py

@@ -15,6 +15,10 @@
 # limitations under the License.
 """Contract tests for DatasetReader."""
 
+import pytest
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.dataset_reader import DatasetReader
 from lerobot.utils.import_utils import get_safe_default_codec
 

tests/datasets/test_dataset_tools.py

@@ -21,6 +21,8 @@ import numpy as np
 import pytest
 import torch
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.dataset_tools import (
     add_features,
     delete_episodes,

tests/datasets/test_dataset_utils.py

@@ -16,7 +16,10 @@
 
 import pytest
 import torch
-from datasets import Dataset
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
+from datasets import Dataset  # noqa: E402
 from huggingface_hub import DatasetCard
 
 from lerobot.datasets.io_utils import hf_transform_to_torch

tests/datasets/test_dataset_writer.py

@@ -23,6 +23,8 @@ import pytest
 import torch
 from PIL import Image
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.dataset_writer import _encode_video_worker
 from lerobot.datasets.lerobot_dataset import LeRobotDataset
 from lerobot.datasets.utils import DEFAULT_IMAGE_PATH

tests/datasets/test_datasets.py

@@ -21,6 +21,9 @@ from pathlib import Path
 import numpy as np
 import pytest
 import torch
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from huggingface_hub import HfApi
 from PIL import Image
 from safetensors.torch import load_file

tests/datasets/test_delta_timestamps.py

@@ -13,6 +13,8 @@
 # limitations under the License.
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.feature_utils import (
     check_delta_timestamps,
     get_delta_indices,

tests/datasets/test_image_transforms.py

@@ -21,6 +21,8 @@ from safetensors.torch import load_file
 from torchvision.transforms import v2
 from torchvision.transforms.v2 import functional as F  # noqa: N812
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.scripts.lerobot_imgtransform_viz import (
     save_all_transforms,
     save_each_transform,

tests/datasets/test_image_writer.py

@@ -20,6 +20,8 @@ import numpy as np
 import pytest
 from PIL import Image
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.image_writer import (
     AsyncImageWriter,
     image_array_to_pil_image,

tests/datasets/test_lerobot_dataset.py

@@ -25,6 +25,8 @@ from unittest.mock import Mock
 import pytest
 import torch
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 import lerobot.datasets.dataset_metadata as dataset_metadata_module
 import lerobot.datasets.lerobot_dataset as lerobot_dataset_module
 from lerobot.datasets.dataset_metadata import LeRobotDatasetMetadata

tests/datasets/test_quantiles_dataset_integration.py

@@ -19,6 +19,8 @@
 import numpy as np
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.lerobot_dataset import LeRobotDataset
 
 

tests/datasets/test_sampler.py

@@ -17,7 +17,10 @@ import logging
 
 import pytest
 import torch
-from datasets import Dataset
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
+from datasets import Dataset  # noqa: E402
 
 from lerobot.datasets.io_utils import (
     hf_transform_to_torch,

tests/datasets/test_streaming.py

@@ -17,6 +17,8 @@ import numpy as np
 import pytest
 import torch
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.streaming_dataset import StreamingLeRobotDataset
 from lerobot.datasets.utils import safe_shard
 from lerobot.utils.constants import ACTION

tests/datasets/test_streaming_video_encoder.py

@@ -20,10 +20,13 @@ import queue
 import threading
 from unittest.mock import patch
 
-import av
 import numpy as np
 import pytest
 
+pytest.importorskip("av", reason="av is required (install lerobot[dataset])")
+
+import av  # noqa: E402
+
 from lerobot.datasets.video_utils import (
     VALID_VIDEO_CODECS,
     StreamingVideoEncoder,

tests/datasets/test_subtask_dataset.py

@@ -23,8 +23,11 @@ These tests verify that:
 - Subtask handling gracefully handles missing data
 """
 
-import pandas as pd
 import pytest
+
+pytest.importorskip("pandas", reason="pandas is required (install lerobot[dataset])")
+
+import pandas as pd  # noqa: E402
 import torch
 
 from lerobot.datasets.lerobot_dataset import LeRobotDataset

tests/datasets/test_visualize_dataset.py

@@ -15,6 +15,8 @@
 # limitations under the License.
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.scripts.lerobot_dataset_viz import visualize_dataset
 
 

tests/motors/test_motors_bus.py

@@ -19,6 +19,8 @@ from unittest.mock import patch
 
 import pytest
 
+pytest.importorskip("serial", reason="pyserial is required (install lerobot[hardware])")
+
 from lerobot.motors.motors_bus import (
     Motor,
     MotorNormMode,

tests/policies/groot/test_groot_lerobot.py

@@ -31,7 +31,7 @@ from lerobot.policies.groot.processor_groot import make_groot_pre_post_processor
 from lerobot.processor import PolicyProcessorPipeline
 from lerobot.types import PolicyAction
 from lerobot.utils.device_utils import auto_select_torch_device
-from tests.utils import require_cuda  # noqa: E402
+from tests.utils import require_cuda
 
 pytest.importorskip("transformers")
 

tests/policies/smolvla/test_smolvla_rtc.py

@@ -19,12 +19,12 @@
 import pytest
 import torch
 
-from lerobot.configs.types import FeatureType, PolicyFeature, RTCAttentionSchedule  # noqa: E402
-from lerobot.policies.factory import make_pre_post_processors  # noqa: E402
-from lerobot.policies.rtc.configuration_rtc import RTCConfig  # noqa: E402
+from lerobot.configs.types import FeatureType, PolicyFeature, RTCAttentionSchedule
+from lerobot.policies.factory import make_pre_post_processors
+from lerobot.policies.rtc.configuration_rtc import RTCConfig
 from lerobot.policies.smolvla.configuration_smolvla import SmolVLAConfig  # noqa: F401
-from lerobot.utils.random_utils import set_seed  # noqa: E402
-from tests.utils import require_cuda, skip_if_package_missing  # noqa: E402
+from lerobot.utils.random_utils import set_seed
+from tests.utils import require_cuda, skip_if_package_missing
 
 
 @skip_if_package_missing("transformers")

tests/policies/test_policies.py

@@ -20,6 +20,9 @@ from pathlib import Path
 import einops
 import pytest
 import torch
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from packaging import version
 from safetensors.torch import load_file
 

tests/policies/test_relative_actions.py

@@ -10,6 +10,8 @@ import numpy as np
 import pytest
 import torch
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.configs.types import FeatureType, NormalizationMode, PolicyFeature
 from lerobot.datasets.compute_stats import get_feature_stats
 from lerobot.datasets.lerobot_dataset import LeRobotDataset

tests/processor/test_pipeline.py

@@ -25,6 +25,8 @@ import pytest
 import torch
 import torch.nn as nn
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.configs.types import FeatureType, PipelineFeatureType, PolicyFeature
 from lerobot.datasets.pipeline_features import aggregate_pipeline_dataset_features
 from lerobot.processor import (

tests/rl/test_actor.py

@@ -19,6 +19,9 @@ from unittest.mock import patch
 
 import pytest
 import torch
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from torch.multiprocessing import Event, Queue
 
 from lerobot.utils.constants import OBS_STR

tests/rl/test_actor_learner.py

@@ -20,6 +20,9 @@ import time
 
 import pytest
 import torch
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from torch.multiprocessing import Event, Queue
 
 from lerobot.configs.train import TrainRLServerPipelineConfig

tests/scripts/test_edit_dataset_parsing.py

@@ -17,6 +17,8 @@
 import draccus
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.scripts.lerobot_edit_dataset import (
     ConvertImageToVideoConfig,
     DeleteEpisodesConfig,

tests/test_control_robot.py

@@ -16,6 +16,10 @@
 
 from unittest.mock import patch
 
+import pytest
+
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.scripts.lerobot_calibrate import CalibrateConfig, calibrate
 from lerobot.scripts.lerobot_record import DatasetRecordConfig, RecordConfig, record
 from lerobot.scripts.lerobot_replay import DatasetReplayConfig, ReplayConfig, replay

tests/training/test_multi_gpu.py

@@ -33,6 +33,8 @@ from pathlib import Path
 import pytest
 import torch
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.datasets.lerobot_dataset import LeRobotDataset
 
 

tests/training/test_visual_validation.py

@@ -31,6 +31,8 @@ from pathlib import Path
 import numpy as np
 import pytest
 
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
+
 from lerobot.configs.default import DatasetConfig
 from lerobot.configs.policies import PreTrainedConfig
 from lerobot.configs.train import TrainPipelineConfig

tests/utils/test_replay_buffer.py

@@ -20,6 +20,7 @@ from collections.abc import Callable
 import pytest
 
 pytest.importorskip("grpc")
+pytest.importorskip("datasets", reason="datasets is required (install lerobot[dataset])")
 
 import torch  # noqa: E402
 

tests/utils/test_visualization_utils.py

@@ -21,6 +21,8 @@ from types import SimpleNamespace
 import numpy as np
 import pytest
 
+pytest.importorskip("rerun", reason="rerun-sdk is required (install lerobot[viz])")
+
 from lerobot.types import TransitionKey
 from lerobot.utils.constants import OBS_STATE