Allow correspondents to be deleted without deleting their documents

Fixes #235

src/documents/migrations/0018_auto_20170715_1712.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.5 on 2017-07-15 17:12
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('documents', '0017_auto_20170512_0507'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='document',
+            name='correspondent',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='documents', to='documents.Correspondent'),
+        ),
+    ]

src/documents/models.py

@@ -172,7 +172,12 @@ class Document(models.Model):
     TYPES = (TYPE_PDF, TYPE_PNG, TYPE_JPG, TYPE_GIF, TYPE_TIF,)
 
     correspondent = models.ForeignKey(
-        Correspondent, blank=True, null=True, related_name="documents")
+        Correspondent,
+        blank=True,
+        null=True,
+        related_name="documents",
+        on_delete=models.SET_NULL
+    )
 
     title = models.CharField(max_length=128, blank=True, db_index=True)
 

src/documents/tests/factories.py

@@ -0,0 +1,17 @@
+import factory
+
+from ..models import Document, Correspondent
+
+
+class CorrespondentFactory(factory.DjangoModelFactory):
+
+    class Meta:
+        model = Correspondent
+
+    name = factory.Faker("name")
+
+
+class DocumentFactory(factory.DjangoModelFactory):
+
+    class Meta:
+        model = Document

src/documents/tests/test_models.py

@@ -0,0 +1,31 @@
+from django.test import TestCase
+
+from ..models import Document, Correspondent
+from .factories import DocumentFactory, CorrespondentFactory
+
+
+class CorrespondentTestCase(TestCase):
+
+    def test___str__(self):
+        for s in ("test", "οχι", "test with fun_charÅc'\"terß"):
+            correspondent = CorrespondentFactory.create(name=s)
+            self.assertEqual(str(correspondent), s)
+
+
+class DocumentTestCase(TestCase):
+
+    def test_correspondent_deletion_does_not_cascade(self):
+
+        self.assertEqual(Correspondent.objects.all().count(), 0)
+        correspondent = CorrespondentFactory.create()
+        self.assertEqual(Correspondent.objects.all().count(), 1)
+
+        self.assertEqual(Document.objects.all().count(), 0)
+        DocumentFactory.create(correspondent=correspondent)
+        self.assertEqual(Document.objects.all().count(), 1)
+        self.assertIsNotNone(Document.objects.all().first().correspondent)
+
+        correspondent.delete()
+        self.assertEqual(Correspondent.objects.all().count(), 0)
+        self.assertEqual(Document.objects.all().count(), 1)
+        self.assertIsNone(Document.objects.all().first().correspondent)