diff --git a/openedx/core/djangoapps/content/block_structure/tests/helpers.py b/openedx/core/djangoapps/content/block_structure/tests/helpers.py
index 93655c79e16e..84c99d71e1f0 100644
--- a/openedx/core/djangoapps/content/block_structure/tests/helpers.py
+++ b/openedx/core/djangoapps/content/block_structure/tests/helpers.py
@@ -7,6 +7,7 @@
 from uuid import uuid4
 from unittest.mock import patch
 
+from opaque_keys.edx.keys import CourseKey
 from opaque_keys.edx.locator import BlockUsageLocator, CourseLocator
 
 from xmodule.modulestore.exceptions import ItemNotFoundError
@@ -264,7 +265,7 @@ def block_key_factory(self, block_id):
         Override this method if the block_key should be anything
         different from the index integer values in the Children Maps.
         """
-        return block_id
+        return CourseKey.from_string("course-v1:org+course+run").make_usage_key("html", str(block_id))
 
     def create_block_structure(self, children_map, block_structure_cls=BlockStructureBlockData):
         """
@@ -274,10 +275,12 @@ def create_block_structure(self, children_map, block_structure_cls=BlockStructur
         # create empty block structure
         block_structure = block_structure_cls(root_block_usage_key=self.block_key_factory(0))
 
-        # _add_relation
+        # _add_relation and blocks
         for parent, children in enumerate(children_map):
+            block_structure._get_or_create_block(self.block_key_factory(parent))
             for child in children:
                 block_structure._add_relation(self.block_key_factory(parent), self.block_key_factory(child))  # pylint: disable=protected-access
+                block_structure._get_or_create_block(self.block_key_factory(child))
         return block_structure
 
     def get_parents_map(self, children_map):