Modify Skill app: changes on skill_type model (#63)

skills/migrations/0005_remove_skill_skill_type_skill_skill_type.py

@@ -0,0 +1,40 @@
+# Generated by Django 4.2.11 on 2025-02-27 21:51
+
+from django.db import migrations, models
+import django.db.models.deletion
+from skills.models import Skill
+
+def move_skill_type_fk(apps, schema_editor): # pragma: no cover
+    for skill in apps.get_model('skills', 'Skill').objects.all():
+        skill.skill_class = skill.skill_type.all().first()
+        skill.save()
+
+def move_skill_type_m2m(apps, schema_editor): # pragma: no cover
+    for skill in apps.get_model('skills', 'Skill').objects.all():
+        skill.skill_type.add(skill.skill_class)
+        skill.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('skills', '0004_alter_skill_skill_type_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='skill',
+            name='skill_class',
+            field=models.ForeignKey(blank=True, help_text='ID of the another skill that this skill is a subtype of.', null=True, on_delete=django.db.models.deletion.SET_NULL, to='skills.skill', verbose_name='Skill type'),
+        ),
+        migrations.RunPython(move_skill_type_fk, move_skill_type_m2m),
+        migrations.RemoveField(
+            model_name='skill',
+            name='skill_type',
+        ),
+        migrations.RenameField(
+            model_name='skill',
+            old_name='skill_class',
+            new_name='skill_type',
+        ),
+    ]

skills/models.py

@@ -1,6 +1,7 @@
 from django.db import models
 from django.core.validators import RegexValidator
 from django.utils import timezone
+from django.core.exceptions import ValidationError
 
 
 qid_form_validator = RegexValidator(regex=r"^Q\d+$", message="Field must be in the format \"Q123456789\"")
@@ -13,12 +14,23 @@ class Skill(models.Model):
         help_text="Wikidata item ID of the skill.",
         validators=[qid_form_validator]
     )
-    skill_type = models.ManyToManyField(
+    skill_type = models.ForeignKey(
         "self", 
-        verbose_name="Skill type", symmetrical=False, blank=True,
+        verbose_name="Skill type", blank=True, on_delete=models.SET_NULL, null=True,
         help_text="ID of the another skill that this skill is a subtype of."
     )
     skill_date_of_creation = models.DateTimeField(default=timezone.now)
 
     def __str__(self):
-        return self.skill_wikidata_item
+        return self.skill_wikidata_item
+
+    def save(self, *args, **kwargs):
+        if self.skill_type:
+            parent_skill = self.skill_type
+            level = 1
+            while parent_skill.skill_type:
+                parent_skill = parent_skill.skill_type
+                level += 1
+                if level >= 3:
+                    raise ValidationError("Skills cannot be nested more than 3 levels deep.")
+        super().save(*args, **kwargs)

skills/tests/test_models.py

@@ -1,6 +1,7 @@
 from django.test import TestCase
 from django.utils import timezone
 from skills.models import Skill
+from django.core.exceptions import ValidationError
 
 class SkillModelTest(TestCase):
     def test_skill_creation(self):
@@ -15,3 +16,21 @@ def test_skill_str(self):
             skill_wikidata_item="Q123456789"
         )
         self.assertEqual(str(skill), "Q123456789")
+
+    def test_skill_four_levels_deep(self):
+        skill1 = Skill.objects.create(
+            skill_wikidata_item="Q123456789"
+        )
+        skill2 = Skill.objects.create(
+            skill_wikidata_item="Q123456780",
+            skill_type=skill1
+        )
+        skill3 = Skill.objects.create(
+            skill_wikidata_item="Q123456781",
+            skill_type=skill2
+        )
+        with self.assertRaises(ValidationError):
+            Skill.objects.create(
+                skill_wikidata_item="Q123456782",
+                skill_type=skill3
+            )

skills/tests/test_views.py

@@ -42,11 +42,6 @@ def test_create_skill(self):
         serializer = SkillSerializer(skill)
         self.assertEqual(response.data, serializer.data)
 
-        options_response = self.client.options('/skill/1/')
-        expected_choices = [{'value': 1, 'display_name': 'Q123456789'}, {'value': 2, 'display_name': 'Q987654321'}]
-        self.assertEqual(options_response.status_code, status.HTTP_200_OK)
-        self.assertEqual(options_response.data['actions']['PUT']['skill_type']['choices'], expected_choices)
-
     def test_create_skill_nostaff(self):
         self.user.is_staff = False
         self.user.save()
@@ -112,8 +107,7 @@ def setUp(self):
         self.client = APIClient()
         self.client.force_authenticate(self.user)
         first = Skill.objects.create(skill_wikidata_item='Q123456789')
-        second = Skill.objects.create(skill_wikidata_item='Q987654321')
-        second.skill_type.add(first)
+        Skill.objects.create(skill_wikidata_item='Q987654321', skill_type=first)
 
     def test_get_skills_by_type(self):
         response = self.client.get('/skills_by_type/1/')