Bugfix: Add tests for image deletion and fix mixed image-video deletion (#2592)

* Add tests for image deletion and fix mixed-image-video deletion

* Fix docstring whitespace

* Remove debug print

Signed-off-by: Alex Tyshka <atyshka15@gmail.com>

* Remove inaccurate comment

* Remove batched video test

---------

Signed-off-by: Alex Tyshka <atyshka15@gmail.com>

src/lerobot/datasets/lerobot_dataset.py

@@ -1498,7 +1498,7 @@ class LeRobotDataset(torch.utils.data.Dataset):
             episode_index = self.episode_buffer["episode_index"]
             if isinstance(episode_index, np.ndarray):
                 episode_index = episode_index.item() if episode_index.size == 1 else episode_index[0]
-            for cam_key in self.meta.camera_keys:
+            for cam_key in self.meta.image_keys:
                 img_dir = self._get_image_file_dir(episode_index, cam_key)
                 if img_dir.is_dir():
                     shutil.rmtree(img_dir)

tests/datasets/test_datasets.py

@@ -352,6 +352,65 @@ def test_image_array_to_pil_image_wrong_range_float_0_255():
         image_array_to_pil_image(image)
 
 
+def test_tmp_image_deletion(tmp_path, empty_lerobot_dataset_factory):
+    """Verify temporary image directories are removed for image features after saving episode."""
+    # Image feature: images should be deleted after saving episode
+    image_key = "image"
+    features_image = {
+        image_key: {"dtype": "image", "shape": DUMMY_CHW, "names": ["channels", "height", "width"]}
+    }
+    ds_img = empty_lerobot_dataset_factory(root=tmp_path / "img", features=features_image)
+    ds_img.add_frame({"image": np.random.rand(*DUMMY_CHW), "task": "Dummy task"})
+    ds_img.save_episode()
+    img_dir = ds_img._get_image_file_dir(0, image_key)
+    assert not img_dir.exists(), "Temporary image directory should be removed for image features"
+
+
+def test_tmp_video_deletion(tmp_path, empty_lerobot_dataset_factory):
+    """Verify temporary image directories are removed for video encoding when `batch_encoding_size == 1`."""
+    # Video feature: when batch_encoding_size == 1 temporary images should be deleted
+    vid_key = "video"
+    features_video = {
+        vid_key: {"dtype": "video", "shape": DUMMY_CHW, "names": ["channels", "height", "width"]}
+    }
+
+    ds_vid = empty_lerobot_dataset_factory(root=tmp_path / "vid", features=features_video)
+    ds_vid.batch_encoding_size = 1
+    ds_vid.add_frame({vid_key: np.random.rand(*DUMMY_CHW), "task": "Dummy task"})
+    ds_vid.save_episode()
+    vid_img_dir = ds_vid._get_image_file_dir(0, vid_key)
+    assert not vid_img_dir.exists(), (
+        "Temporary image directory should be removed when batch_encoding_size == 1"
+    )
+
+
+def test_tmp_mixed_deletion(tmp_path, empty_lerobot_dataset_factory):
+    """Verify temporary image directories are removed appropriately when both image and video features are present."""
+    image_key = "image"
+    vid_key = "video"
+    features_mixed = {
+        image_key: {"dtype": "image", "shape": DUMMY_CHW, "names": ["channels", "height", "width"]},
+        vid_key: {"dtype": "video", "shape": DUMMY_HWC, "names": ["height", "width", "channels"]},
+    }
+    ds_mixed = empty_lerobot_dataset_factory(
+        root=tmp_path / "mixed", features=features_mixed, batch_encoding_size=2
+    )
+    ds_mixed.add_frame(
+        {
+            "image": np.random.rand(*DUMMY_CHW),
+            "video": np.random.rand(*DUMMY_HWC),
+            "task": "Dummy task",
+        }
+    )
+    ds_mixed.save_episode()
+    img_dir = ds_mixed._get_image_file_dir(0, image_key)
+    vid_img_dir = ds_mixed._get_image_file_dir(0, vid_key)
+    assert not img_dir.exists(), "Temporary image directory should be removed for image features"
+    assert vid_img_dir.exists(), (
+        "Temporary image directory should not be removed for video features when batch_encoding_size == 2"
+    )
+
+
 # TODO(aliberts):
 # - [ ] test various attributes & state from init and create
 # - [ ] test init with episodes and check num_frames