Empêcher la création d'un objectif ayant pour slug 'non-classes'

Ce slug est utilisé pour afficher les contenus qui n'ont aucun
objectif attribué.

zds/tutorialv2/migrations/0038_goals_forbid_unclassified_slug.py

@@ -0,0 +1,26 @@
+# Generated by Django 3.2.19 on 2023-06-18 11:36
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("tutorialv2", "0037_labels"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="goal",
+            name="slug",
+            field=models.SlugField(
+                max_length=80,
+                unique=True,
+                validators=[
+                    django.core.validators.RegexValidator(
+                        "^non-classes$", inverse_match=True, message="Ce slug est réservé."
+                    )
+                ],
+            ),
+        ),
+    ]

zds/tutorialv2/models/goals.py

@@ -1,4 +1,6 @@
+from django.core.validators import RegexValidator
 from django.db import models
+from django.utils.translation import gettext_lazy as _
 
 
 class Goal(models.Model):
@@ -9,14 +11,22 @@ class Goal(models.Model):
     computer science, etc.) or the tags (even more precise).
     """
 
+    SLUG_UNCLASSIFIED = "non-classes"
+
     class Meta:
         verbose_name = "Objectif"
         verbose_name_plural = "Objectifs"
 
     name = models.CharField("Nom", max_length=80)
     description = models.TextField("Description", blank=True)
     position = models.IntegerField("Position", default=0, db_index=True)
-    slug = models.SlugField(max_length=80, unique=True)
+    slug = models.SlugField(
+        max_length=80,
+        unique=True,
+        validators=[
+            RegexValidator("^" + SLUG_UNCLASSIFIED + "$", message=_("Ce slug est réservé."), inverse_match=True)
+        ],
+    )
 
     def __str__(self):
         return self.name

zds/tutorialv2/tests/tests_views/tests_viewcontentsbygoal.py

@@ -17,3 +17,13 @@ def test_page_content(self):
             self.assertContains(response, goal.name)
         for content in self.contents:
             self.assertContains(response, content.title)
+
+    def test_forbid_slug_unclassified(self):
+        goal = Goal(name="Invalid", slug=Goal.SLUG_UNCLASSIFIED)
+        self.assertRaises(ValidationError, goal.full_clean)
+
+        goal = Goal(name="Almost invalid", slug=Goal.SLUG_UNCLASSIFIED + "z")
+        goal.full_clean()
+
+        goal = Goal(name="Valid", slug="valid-slug")
+        goal.full_clean()