fix: revision after review

xmodule/split_test_block.py

@@ -174,13 +174,19 @@ def child(self):
         """
         Return the user bound child block for the partition or None.
 
-        We are using try/except block here because we ran into issues with
-        CachingDescriptorSystem has no attribute when we get an icon for the split_test xblock.
+        Handles the AttributeError exception that may occur when attempting to retrieve
+        an icon for the split_test xblock within the CMS.
         """
         try:
-            return self.runtime.get_block_for_descriptor(self.child_block)
+            if self.child_block is not None:
+                return self.runtime.get_block_for_descriptor(self.child_block)
+            else:
+                return None
         except AttributeError:
-            log.warning("Error while getting block for descriptor")
+            log.warning(
+                "Error while getting block instance for descriptor with location: [%s]",
+                self.location
+            )
             return None
 
     def get_child_block_by_location(self, location):
@@ -218,20 +224,30 @@ def get_child_blocks(self):
         """
         For grading--return just the chosen child.
 
-        We are using try/except block here because we ran into issues with
-        User service being undefined when we get an icon for the split_test xblock.
+        Handles the NoSuchServiceError and ValueError exception that may occur when attempting to retrieve
+        an icon for the split_test xblock within the CMS.
         """
         try:
             group_id = self.get_group_id()
         except NoSuchServiceError:
-            log.warning("Error while getting user service in runtime")
+            log.warning(
+                "Error while getting user service in runtime with location: [%s]",
+                self.location
+            )
+            return []
+        except ValueError:
+            log.warning(
+                "Error while getting group ID for partition with location: [%s]",
+                self.location
+            )
             return []
 
         if group_id is None:
             return []
 
         # group_id_to_child comes from json, so it has to have string keys
         str_group_id = str(group_id)
+        child_block = None
         if str_group_id in self.group_id_to_child:
             child_location = self.group_id_to_child[str_group_id]
             child_block = self.get_child_block_by_location(child_location)