fix: cast grading policy corretly as numbers (#273)

Fixes an issue with some courses causing the progress page to crash

Author: nsprenkle

lms/djangoapps/course_home_api/progress/api.py

@@ -130,10 +130,10 @@ def _build_policy_map(self) -> dict:
         policy_map = {}
         for policy in self.grading_policy.get('GRADER', []):
             policy_map[policy.get('type')] = {
-                'weight': policy.get('weight', 0.0),
+                'weight': float(policy.get('weight', 0.0) or 0.0),
                 'short_label': policy.get('short_label', ''),
-                'num_droppable': policy.get('drop_count', 0),
-                'num_total': policy.get('min_count', 0),
+                'num_droppable': int(policy.get('drop_count', 0) or 0),
+                'num_total': int(policy.get('min_count', 0) or 0),
             }
         return policy_map
 

lms/djangoapps/course_home_api/progress/tests/test_api.py

@@ -87,6 +87,15 @@ def _make_subsection(fmt, earned, possible, show_corr, *, due_delta_days=None, i
         ],
         {'avg': 0.0, 'weighted': 0.0, 'hidden': 'all', 'final': 0.0, 'last_grade_publish_date_days': 7},
     ),
+    (
+        'string_typed_policy_counts',
+        {'type': 'Homework', 'weight': '1.0', 'drop_count': '1', 'min_count': '2', 'short_label': 'HW'},
+        [
+            _make_subsection('Homework', 1, 1, ShowCorrectness.ALWAYS),
+            _make_subsection('Homework', 0, 1, ShowCorrectness.ALWAYS),
+        ],
+        {'avg': 1.0, 'weighted': 1.0, 'hidden': 'none', 'final': 1.0},
+    ),
 ]
 
 
@@ -187,7 +196,7 @@ def test_aggregate_assignment_type_grade_summary_scenarios(self):
                 assert row['average_grade'] == expected['avg']
                 assert row['weighted_grade'] == expected['weighted']
                 assert row['has_hidden_contribution'] == expected['hidden']
-                assert row['num_droppable'] == policy['drop_count']
+                assert row['num_droppable'] == int(policy['drop_count'])
                 assert (row['last_grade_publish_date'] is not None) == (
                     'last_grade_publish_date_days' in expected
                 )