Fix: Missing test split for COCO parser (#349)

Author: kozlov721

luxonis_ml/data/parsers/coco_parser.py

@@ -162,7 +162,12 @@ def from_dir(
             image_dir=val_paths["image_dir"], annotation_path=val_ann_path
         )
 
-        if split_val_to_test and dir_format == Format.FIFTYONE:
+        if split_val_to_test or len(splits) < 3:
+            if not split_val_to_test:
+                logger.warning(
+                    "Splitting validation set into validation and test sets, "
+                    "as no test split is present in the dataset."
+                )
             split_point = round(len(_added_val_imgs) * 0.5)
             added_val_imgs = _added_val_imgs[:split_point]
             added_test_imgs = _added_val_imgs[split_point:]