[3.2.x] Refs #29721 -- Simplified migration used to test atomic recording.

This makes sure atomic recording of migration application is used when
the schema editor doesn't defer any statement.

Backport of 533a5835784b95335c8373b6d0b9495b3834e96e from master

tests/migrations/test_executor.py

@@ -1,11 +1,12 @@
 from unittest import mock
 
 from django.apps.registry import apps as global_apps
-from django.db import DatabaseError, connection
+from django.db import DatabaseError, connection, migrations, models
 from django.db.migrations.exceptions import InvalidMigrationPlan
 from django.db.migrations.executor import MigrationExecutor
 from django.db.migrations.graph import MigrationGraph
 from django.db.migrations.recorder import MigrationRecorder
+from django.db.migrations.state import ProjectState
 from django.test import (
     SimpleTestCase, modify_settings, override_settings, skipUnlessDBFeature,
 )
@@ -655,18 +656,33 @@ class ExecutorTests(MigrationTestBase):
     # When the feature is False, the operation and the record won't be
     # performed in a transaction and the test will systematically pass.
     @skipUnlessDBFeature('can_rollback_ddl')
-    @override_settings(MIGRATION_MODULES={'migrations': 'migrations.test_migrations'})
     def test_migrations_applied_and_recorded_atomically(self):
         """Migrations are applied and recorded atomically."""
+        class Migration(migrations.Migration):
+            operations = [
+                migrations.CreateModel('model', [
+                    ('id', models.AutoField(primary_key=True)),
+                ]),
+            ]
+
         executor = MigrationExecutor(connection)
         with mock.patch('django.db.migrations.executor.MigrationExecutor.record_migration') as record_migration:
             record_migration.side_effect = RuntimeError('Recording migration failed.')
             with self.assertRaisesMessage(RuntimeError, 'Recording migration failed.'):
+                executor.apply_migration(
+                    ProjectState(),
+                    Migration('0001_initial', 'record_migration'),
+                )
                 executor.migrate([('migrations', '0001_initial')])
         # The migration isn't recorded as applied since it failed.
         migration_recorder = MigrationRecorder(connection)
-        self.assertFalse(migration_recorder.migration_qs.filter(app='migrations', name='0001_initial').exists())
-        self.assertTableNotExists('migrations_author')
+        self.assertIs(
+            migration_recorder.migration_qs.filter(
+                app='record_migration', name='0001_initial',
+            ).exists(),
+            False,
+        )
+        self.assertTableNotExists('record_migration_model')
 
 
 class FakeLoader: