LEARNER-8158 - Fixed descendants typo and added tests

LEARNER-8158 
Fixed descendants typo and added tests

lms/djangoapps/course_api/blocks/tests/test_views.py

@@ -465,3 +465,15 @@ class TestBlocksInCourseView(TestBlocksView, CompletionWaffleTestMixin):  # pyli
         })
         for block_id in self.non_orphaned_block_usage_keys:
             assert response.data['blocks'][block_id].get('completion')
+
+    def test_completion_all_course_with_nav_depth(self):
+        # when we include nav_depth we get descendants in parent nodes
+        for block in self.non_orphaned_raw_block_usage_keys:
+            submit_completions_for_testing(self.user, [block])
+        response = self.verify_response(params={
+            'depth': 'all',
+            'nav_depth': 3,
+            'requested_fields': ['completion'],
+        })
+        for block_id in self.non_orphaned_block_usage_keys:
+            assert response.data['blocks'][block_id].get('completion')

lms/djangoapps/course_api/blocks/views.py

@@ -346,7 +346,7 @@ def recurse_mark_complete(block_id, blocks):
     if block.get('completion') == 1:
         return
 
-    child_blocks = block.get('children', block.get('descendents'))
+    child_blocks = block.get('children', block.get('descendants'))
     # Unit blocks(blocks with no children) completion is being marked by patch call to completion service.
     if child_blocks:
         for child_block in child_blocks: