Add a MinValueValidator on TranscriptioEntity.length

arkindex/documents/migrations/0032_alter_transcriptionentity_length.py

+# Generated by Django 3.1.7 on 2021-04-28 10:10
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('documents', '0031_add_indexable_fields'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='transcriptionentity',
+            name='length',
+            field=models.PositiveIntegerField(validators=[django.core.validators.MinValueValidator(1)]),
+        ),
+    ]

arkindex/documents/models.py

@@ -6,6 +6,7 @@ from django.contrib.contenttypes.fields import GenericRelation
 from django.contrib.postgres.fields import HStoreField
 from django.contrib.postgres.indexes import GinIndex
 from django.core.exceptions import ValidationError
+from django.core.validators import MinValueValidator
 from django.db import models, transaction
 from django.db.models import Q
 from django.utils.functional import cached_property
@@ -427,7 +428,7 @@ class TranscriptionEntity(models.Model):
         related_name='transcription_entities',
     )
     offset = models.PositiveIntegerField()
-    length = models.PositiveIntegerField()
+    length = models.PositiveIntegerField(validators=[MinValueValidator(1)])
 
     class Meta:
         unique_together = (

arkindex/documents/serializers/entities.py

@@ -195,7 +195,7 @@ class TranscriptionEntitySerializer(serializers.ModelSerializer):
     Transcription element must be passed in serializer context
     """
     offset = serializers.IntegerField(min_value=0)
-    length = serializers.IntegerField(min_value=0)
+    length = serializers.IntegerField(min_value=1)
 
     class Meta:
         model = TranscriptionEntity

arkindex/documents/tests/test_entities_api.py

@@ -494,6 +494,23 @@ class TestEntitiesAPI(FixtureAPITestCase):
             {'transcription': ['invalid UUID or Corpus write-access is forbidden']}
         )
 
+    def test_create_transcription_entity_wrong_length(self):
+        self.client.force_login(self.user)
+        response = self.client.post(
+            reverse('api:transcription-entity-create', kwargs={'pk': str(self.transcription.id)}),
+            data={
+                'entity': str(self.entity.id),
+                'offset': 4,
+                'length': 0
+            },
+            format='json'
+        )
+        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
+        self.assertDictEqual(
+            response.json(),
+            {'length': ['Ensure this value is greater than or equal to 1.']}
+        )
+
     def test_create_transcription_entity_different_corpus(self):
         self.client.force_login(self.user)
         ent = Entity.objects.create(