add validation for the field score_max

backend/tournesol/models/comparisons.py

@@ -5,12 +5,11 @@
 import uuid
 
 import computed_property
-from django.core.validators import MaxValueValidator, MinValueValidator
+from django.core.validators import MinValueValidator
 from django.db import models
 from django.db.models import F, ObjectDoesNotExist, Q
 
 from core.models import User
-from tournesol.utils.constants import COMPARISON_MAX
 
 from .poll import Poll
 
@@ -149,10 +148,15 @@ def __str__(self):
         return f"{self.comparison}/{self.criteria}/{self.score}"
 
     def save(self, *args, **kwargs):
-        if self.score_max is not None:
-            if abs(self.score) > abs(self.score_max):
-                raise ValueError(
-                    f"The absolute value of the score {self.score} given to the criterion "
-                    f"{self.criteria} can't be superior to the score_max {self.score_max}."
-                )
+        if self.score_max is None:
+            raise TypeError("The value of score_max cannot be None.")
+
+        if self.score_max <= 0:
+            raise ValueError("The value of score_max must be greater than or equal to 1.")
+
+        if abs(self.score) > self.score_max:
+            raise ValueError(
+                f"The absolute value of the score {self.score} given to the criterion "
+                f"{self.criteria} can't be greater than the value of score_max {self.score_max}."
+            )
         return super().save(*args, **kwargs)

backend/tournesol/tests/test_model_comparisoncriteriascore.py

@@ -2,7 +2,7 @@
 All test cases of the `ComparisonCriteriaScore` model.
 """
 
-from django.db import IntegrityError, transaction
+from django.core.exceptions import ValidationError
 from django.test import TestCase
 
 from core.tests.factories.user import UserFactory
@@ -21,11 +21,25 @@ class ComparisonCriteriaScoreTestCase(TestCase):
     def setUp(self):
         self.poll = PollWithCriteriasFactory()
         self.user = UserFactory(username=self._user)
-        self.comparison = ComparisonFactory(
-            user=self.user,
-            poll=self.poll,
+        self.comparison = ComparisonFactory(poll=self.poll, user=self.user)
+
+    def test_validators_score_max(self):
+        score = ComparisonCriteriaScore(
+            comparison=self.comparison,
+            criteria=self.poll.main_criteria,
+            score=0,
+            score_max=0,
         )
 
+        # score_max cannot be zero.
+        with self.assertRaises(ValidationError):
+            score.clean_fields()
+
+        score.score_max = -1
+        # score_max cannot be negative.
+        with self.assertRaises(ValidationError):
+            score.clean_fields()
+
     def test_save_validate_score(self):
         score = ComparisonCriteriaScore(
             comparison=self.comparison,
@@ -34,19 +48,48 @@ def test_save_validate_score(self):
             score_max=10,
         )
 
-        # The score cannot be superior to the score_max.
+        # The score cannot be greater than score_max.
         with self.assertRaises(ValueError):
             score.save()
 
         score.score = -11
-        # The absolute value of the score cannot be superior to the score_max.
+        # The absolute value of the score cannot be greater than score_max.
         with self.assertRaises(ValueError):
             score.save()
 
-        # The score can be equal to the magnitude.
+        # The score can be zero.
+        score.score = 0
+        score.save()
+
+        # The score can be equal to the score_max.
         score.score = score.score_max
         score.save()
 
-        # The absolute value of the score can be inferior to the score_max.
-        score.score = 0
+        # The absolute value of the score can be lesser than score_max.
+        score.score = -1
+        score.save()
+
+    def test_save_validate_score_max(self):
+        score = ComparisonCriteriaScore(
+            comparison=self.comparison,
+            criteria=self.poll.main_criteria,
+            score=5,
+            score_max=None,
+        )
+
+        # score_max cannot be None.
+        with self.assertRaises(TypeError):
+            score.save()
+
+        score.score_max = 0
+        # score_max cannot be zero.
+        with self.assertRaises(ValueError):
+            score.save()
+
+        score.score_max = -10
+        # score_max cannot be negative.
+        with self.assertRaises(ValueError):
+            score.save()
+
+        score.score_max = 10
         score.save()