Add unit tests to video dataset to get 100% coverage

Signed-off-by: Daniel Falk <Daniel.Falk.1@FixedIT.ai>

tests/extras/datasets/video/test_sliced_video.py

@@ -30,6 +30,11 @@ def test_slice_sequence_video_last_as_end(self, color_video):
         assert np.all(purple[:, :, 1] == 0)
         assert np.all(purple[:, :, 2] == 255)
 
+    def test_slice_sequence_attribute(self, color_video):
+        """Test that attributes from the base class are reachable from sliced views"""
+        slice_red_green = color_video[:2]
+        assert slice_red_green.fps == color_video.fps
+
     def test_slice_sliced_video(self, color_video):
         """Test slicing and then indexing a SlicedVideo"""
         slice_green_blue_yellow = color_video[1:4]

tests/extras/datasets/video/test_video_objects.py

@@ -21,7 +21,11 @@
     assert_images_equal,
 )
 
-from kedro.extras.datasets.video.video_dataset import GeneratorVideo, SequenceVideo
+from kedro.extras.datasets.video.video_dataset import (
+    FileVideo,
+    GeneratorVideo,
+    SequenceVideo,
+)
 
 
 class TestSequenceVideo:
@@ -145,3 +149,22 @@ def test_file_index_last_by_index(self, color_video_object, purple_frame):
 
     def test_file_index_last(self, color_video_object, purple_frame):
         assert_images_equal(color_video_object[-1], purple_frame)
+
+    def test_file_video_failed_capture(self, mocker):
+        """Validate good behavior on failed decode
+
+        The best behavior in this case is not obvious, the len property of the
+        video object specifies more frames than is actually possible to decode. We
+        cannot know this in advance without spending loads of time to decode all frames
+        in order to count them."""
+        mock_cv2 = mocker.patch("kedro.extras.datasets.video.video_dataset.cv2")
+        mock_cap = mock_cv2.VideoCapture.return_value = mocker.Mock()
+        mock_cap.get.return_value = 2  # Set the length of the video
+        ds = FileVideo("/a/b/c")
+
+        mock_cap.read.return_value = True, np.zeros((1, 1))
+        assert ds[0]
+
+        mock_cap.read.return_value = False, None
+        with pytest.raises(IndexError):
+            ds[1]