Cache for reading annotation

tests/test_add_final_score.py

@@ -9,9 +9,31 @@ import pandas as pd
 from PIL import Image
 
 from copienator.commands import add_final_score
+from copienator import atomic_write_json, read_json
 
 
 class AddFinalScoreTests(unittest.TestCase):
+    def test_statistics_average_all_score_files_and_round_up_without_float_drift(self):
+        with tempfile.TemporaryDirectory() as temporary:
+            root = Path(temporary)
+            returns = root / 'A Rendre'
+            atomic_write_json(returns / 'Alice/score.json', {
+                'Ex 1': '2.0', 'Ex 2': '0.1', 'Ex 3': '', 'Empty': '', 'Zero': 0,
+            })
+            atomic_write_json(returns / 'Bob/score.json', {
+                'Ex 1': 2.01, 'Ex 2': '0.1', 'Ex 3': '3.5', 'Empty': None,
+            })
+            output = root / 'output'
+            output.mkdir()
+            add_final_score.write_score_statistics(returns, output)
+            self.assertEqual(read_json(output / 'stat.json'), {
+                'Ex 1': '2.1', 'Ex 2': '0.1', 'Ex 3': '3.5', 'Empty': '', 'Zero': '0.0',
+            })
+            # Rebuilding uses current returns, without accumulating old averages.
+            atomic_write_json(returns / 'Bob/score.json', {'Ex 1': 4})
+            add_final_score.write_score_statistics(returns, output)
+            self.assertEqual(read_json(output / 'stat.json')['Ex 1'], '3.0')
+
     def test_merged_histogram_is_copied_only_when_selected(self):
         with tempfile.TemporaryDirectory() as temporary:
             root = Path(temporary)
@@ -80,6 +102,7 @@ class AddFinalScoreTests(unittest.TestCase):
             self.assertFalse((output / "Student.pdf").exists())
             self.assertFalse((student / "answers" / "001 - Ex 1.jpg").exists())
             self.assertEqual((output / "histogramme.pdf").read_bytes(), b"histogram")
+            self.assertEqual(read_json(output / "stat.json"), {"Ex 1": "4.0"})
 
     def test_omits_answers_directory_when_it_was_not_generated(self):
         with tempfile.TemporaryDirectory() as temporary: