Fixed #22487: Optional rollback emulation for migrated apps

tests/migration_test_data_persistence/migrations/0001_initial.py

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+
+
+def add_book(apps, schema_editor):
+    apps.get_model("migration_test_data_persistence", "Book").objects.using(
+        schema_editor.connection.alias,
+    ).create(
+        title="I Love Django",
+    )
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Book',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', primary_key=True, serialize=False, auto_created=True)),
+                ('title', models.CharField(max_length=100)),
+            ],
+            options={
+            },
+            bases=(models.Model,),
+        ),
+        migrations.RunPython(
+            add_book,
+        ),
+    ]

tests/migration_test_data_persistence/models.py

@@ -0,0 +1,5 @@
+from django.db import models
+
+
+class Book(models.Model):
+    title = models.CharField(max_length=100)

tests/migration_test_data_persistence/tests.py

@@ -0,0 +1,33 @@
+from django.test import TransactionTestCase
+from .models import Book
+
+
+class MigrationDataPersistenceTestCase(TransactionTestCase):
+    """
+    Tests that data loaded in migrations is available if we set
+    serialized_rollback = True.
+    """
+
+    available_apps = ["migration_test_data_persistence"]
+    serialized_rollback = True
+
+    def test_persistence(self):
+        self.assertEqual(
+            Book.objects.count(),
+            1,
+        )
+
+
+class MigrationDataNoPersistenceTestCase(TransactionTestCase):
+    """
+    Tests the failure case
+    """
+
+    available_apps = ["migration_test_data_persistence"]
+    serialized_rollback = False
+
+    def test_no_persistence(self):
+        self.assertEqual(
+            Book.objects.count(),
+            0,
+        )