diff --git a/test/unit_tests/image_stitcher_test.py b/test/unit_tests/image_stitcher_test.py
index 9f643e2..ff0bb9f 100644
--- a/test/unit_tests/image_stitcher_test.py
+++ b/test/unit_tests/image_stitcher_test.py
@@ -52,7 +52,8 @@ class BoxSplitter:
 
     def __split_and_recurse(self, box, step):
         new_boxes = self.__random_split(box)
-        return chain.from_iterable(self.__tree_recurse(new_boxes, step + 1))
+        new_boxes_per_branch = self.__tree_recurse(new_boxes, step + 1)
+        return chain.from_iterable(new_boxes_per_branch)
 
     def __random_split(self, box):
         splitter = random.choice([self.__split_horizontal, self.__split_vertical])