Fix: return None when no frame data is available in next_frame method

Author: codeSamuraii

src/native/src/bindings.cpp

@@ -40,6 +40,7 @@ NB_MODULE(_viteo, m) {
                     nb::gil_scoped_release release;
                     frame_data = self.next_frame();
                 }
+                if (!frame_data) return nb::none();
                 return create_mlx_array(frame_data, self.height(), self.width());
             },
             "Get next frame as MLX array (None when done)")

tests/test_viteo.py

@@ -123,6 +123,38 @@ def test_iterator(sample_video):
         assert count == 10
 
 
+def test_run_to_end(sample_video):
+    """Test running through all frames to the end."""
+    path = sample_video["path"]
+    if not path.exists():
+        pytest.skip(f"Test video not found: {path}")
+
+    with viteo.open(path) as video:
+        frame_count = 0
+        for frame in video:
+            frame_count += 1
+
+    assert frame_count == video.total_frames
+
+
+def test_last_frame_is_none(sample_video):
+    path = sample_video["path"]
+    if not path.exists():
+        pytest.skip(f"Test video not found: {path}")
+
+    i = 0
+    with viteo.open(path) as video:
+        while True:
+            frame = video.next_frame()
+            if not isinstance(frame, mx.array):
+                break
+
+            i += 1
+
+        assert frame is None
+        assert i == video.total_frames
+
+
 def test_reset(sample_video):
     """Test reset functionality."""
     path = sample_video["path"]