diff --git a/tests/conftest.py b/tests/conftest.py
index bdf3e420..7893b29d 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -6,7 +6,7 @@
 import numpy as np
 import pandas as pd
 from iohub import open_ome_zarr
-from pytest import TempPathFactory, fixture
+from pytest import FixtureRequest, TempPathFactory, fixture
 
 if TYPE_CHECKING:
     from numpy.typing import DTypeLike
@@ -20,6 +20,7 @@ def _build_hcs(
     zyx_shape: tuple[int, int, int],
     dtype: DTypeLike,
     max_value: int | float,
+    sharded: bool = False,
     multiscales: bool = False,
 ):
     dataset = open_ome_zarr(
@@ -27,6 +28,7 @@ def _build_hcs(
         layout="hcs",
         mode="w",
         channel_names=channel_names,
+        version="0.4" if not sharded else "0.5",
     )
     for row in ("A", "B"):
         for col in ("1", "2"):
@@ -37,6 +39,10 @@ def _build_hcs(
                     (
                         np.random.rand(2, len(channel_names), *zyx_shape) * max_value
                     ).astype(dtype),
+                    chunks=(1, 1, 1, *zyx_shape[1:]),
+                    shards_ratio=(2, len(channel_names), zyx_shape[0], 1, 1)
+                    if sharded
+                    else None,
                 )
                 if multiscales:
                     pos["1"] = pos["0"][::2, :, ::2, ::2, ::2]
@@ -59,11 +65,15 @@ def preprocessed_hcs_dataset(tmp_path_factory: TempPathFactory) -> Path:
     return dataset_path
 
 
-@fixture(scope="function")
-def small_hcs_dataset(tmp_path_factory: TempPathFactory) -> Path:
+@fixture(scope="function", params=[False, True])
+def small_hcs_dataset(
+    tmp_path_factory: TempPathFactory, request: FixtureRequest
+) -> Path:
     """Provides a small, not preprocessed HCS OME-Zarr dataset."""
     dataset_path = tmp_path_factory.mktemp("small.zarr")
-    _build_hcs(dataset_path, channel_names, (12, 64, 64), np.uint16, 1)
+    _build_hcs(
+        dataset_path, channel_names, (12, 64, 64), np.uint16, 1, sharded=request.param
+    )
     return dataset_path
 
 
diff --git a/tests/data/test_hcs.py b/tests/data/test_hcs.py
index c71488c4..d45bd17e 100644
--- a/tests/data/test_hcs.py
+++ b/tests/data/test_hcs.py
@@ -1,33 +1,8 @@
-from pathlib import Path
-
 from iohub import open_ome_zarr
 from monai.transforms import RandSpatialCropSamplesd
 from pytest import mark
 
 from viscy.data.hcs import HCSDataModule
-from viscy.trainer import VisCyTrainer
-
-
-@mark.parametrize("default_channels", [True, False])
-def test_preprocess(small_hcs_dataset: Path, default_channels: bool):
-    data_path = small_hcs_dataset
-    if default_channels:
-        channel_names = -1
-    else:
-        with open_ome_zarr(data_path) as dataset:
-            channel_names = dataset.channel_names
-    trainer = VisCyTrainer(accelerator="cpu")
-    trainer.preprocess(data_path, channel_names=channel_names, num_workers=2)
-    with open_ome_zarr(data_path) as dataset:
-        channel_names = dataset.channel_names
-        for channel in channel_names:
-            assert "dataset_statistics" in dataset.zattrs["normalization"][channel]
-        for _, fov in dataset.positions():
-            norm_metadata = fov.zattrs["normalization"]
-            for channel in channel_names:
-                assert channel in norm_metadata
-                assert "dataset_statistics" in norm_metadata[channel]
-                assert "fov_statistics" in norm_metadata[channel]
 
 
 @mark.parametrize("multi_sample_augmentation", [True, False])
diff --git a/tests/preprocessing/test_trainer_preprocess.py b/tests/preprocessing/test_trainer_preprocess.py
new file mode 100644
index 00000000..a65fab17
--- /dev/null
+++ b/tests/preprocessing/test_trainer_preprocess.py
@@ -0,0 +1,28 @@
+from pathlib import Path
+
+from iohub import open_ome_zarr
+from pytest import mark
+
+from viscy.trainer import VisCyTrainer
+
+
+@mark.parametrize("default_channels", [True, False])
+def test_preprocess(small_hcs_dataset: Path, default_channels: bool):
+    data_path = small_hcs_dataset
+    if default_channels:
+        channel_names = -1
+    else:
+        with open_ome_zarr(data_path) as dataset:
+            channel_names = dataset.channel_names
+    trainer = VisCyTrainer(accelerator="cpu")
+    trainer.preprocess(data_path, channel_names=channel_names, num_workers=2)
+    with open_ome_zarr(data_path) as dataset:
+        channel_names = dataset.channel_names
+        for channel in channel_names:
+            assert "dataset_statistics" in dataset.zattrs["normalization"][channel]
+        for _, fov in dataset.positions():
+            norm_metadata = fov.zattrs["normalization"]
+            for channel in channel_names:
+                assert channel in norm_metadata
+                assert "dataset_statistics" in norm_metadata[channel]
+                assert "fov_statistics" in norm_metadata[channel]