fix: fix user quiz stats "divide by zero" (#1997)

users/models.py

@@ -273,7 +273,9 @@ def quiz_answer_success_count_ratio(self) -> float:
                     quiz.stats.aggregate(Avg("answer_success_count"))["answer_success_count__avg"]
                     / quiz.stats.aggregate(Avg("question_count"))["question_count__avg"]
                 )
-        return round(answer_success_count_ratio / quiz_played_count * 100, 2)
+        if quiz_played_count:
+            return round((answer_success_count_ratio / quiz_played_count) * 100, 2)
+        return 0
 
     @property
     def quiz_like_count(self) -> int:

users/tests.py

@@ -3,6 +3,7 @@
 from core import constants
 from questions.factories import QuestionFactory
 from quizs.factories import QuizFactory
+from stats.models import QuizAnswerEvent
 from users import constants as user_constants
 from users.factories import UserFactory
 from users.models import User
@@ -32,6 +33,18 @@ def test_quiz_count(self):
     def test_has_question(self):
         self.assertTrue(self.user.has_question)
 
+    def test_quiz_answer_success_count_ratio(self):
+        self.assertEqual(self.user.quiz_answer_success_count_ratio, 0)
+        # add stats
+        QuizAnswerEvent.objects.create(quiz=self.quiz, answer_success_count=0, question_count=2)
+        self.assertEqual(self.user.quiz_answer_success_count_ratio, 0)
+        QuizAnswerEvent.objects.create(quiz=self.quiz, answer_success_count=1, question_count=2)
+        self.assertEqual(self.user.quiz_answer_success_count_ratio, 25.0)
+        QuizAnswerEvent.objects.create(quiz=self.quiz, answer_success_count=2, question_count=2)
+        self.assertEqual(self.user.quiz_answer_success_count_ratio, 50.0)
+        QuizAnswerEvent.objects.create(quiz=self.quiz, answer_success_count=2, question_count=2)
+        self.assertEqual(self.user.quiz_answer_success_count_ratio, 62.5)
+
 
 class UserModelRoleTest(TestCase):
     @classmethod