diff --git a/lms/djangoapps/course_api/blocks/transformers/blocks_api.py b/lms/djangoapps/course_api/blocks/transformers/blocks_api.py
index b8be4ef29d..94b7c5d3d1 100644
--- a/lms/djangoapps/course_api/blocks/transformers/blocks_api.py
+++ b/lms/djangoapps/course_api/blocks/transformers/blocks_api.py
@@ -13,11 +13,13 @@ class BlocksAPITransformer(BlockStructureTransformer):
     Umbrella transformer that contains all the transformers needed by the
     Course Blocks API.
 
-    Contained Transformers (in this order):
+    Contained Transformers (processed in this order):
         StudentViewTransformer
         BlockCountsTransformer
         BlockDepthTransformer
         BlockNavigationTransformer
+
+    Note: BlockDepthTransformer must be executed before BlockNavigationTransformer.
     """
 
     VERSION = 1
diff --git a/lms/djangoapps/course_api/blocks/transformers/tests/__init__.py b/lms/djangoapps/course_api/blocks/transformers/tests/__init__.py
new file mode 100644
index 0000000000..e69de29bb2