django-test-migrations

import os import pytest from django.conf import settings # Minimal Django settings for testing if not already configured # In a real project, this would typically be in your settings.py if not settings.configured: settings.configure( INSTALLED_APPS=[ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', # Add your app here, e.g., 'myapp' ], DATABASES={ 'default': { 'ENGINE': 'django.db.backends.sqlite3', 'NAME': ':memory:', } }, MIGRATION_MODULES={ # Example for a hypothetical app 'myapp' # 'myapp': 'myapp.migrations' # Uncomment if your app has migrations } ) from django_test_migrations.migrator import Migrator @pytest.fixture(scope='function') def migrator(db) -> Migrator: """Provides a Migrator instance for testing against the 'default' database.""" return Migrator(database='default') def test_my_migration(migrator: Migrator): # Set up the database to a state *before* the migration you want to test # Example: app_label 'myapp', migration name '0001_initial' old_state = migrator.apply_initial_migration(('myapp', '0001_initial')) # Get the model class from the old state # Replace 'MyModel' with your actual model name OldMyModel = old_state.apps.get_model('myapp', 'MyModel') # Create some data that will be affected by the migration # Example: creating an instance with an old field value old_instance = OldMyModel.objects.create(some_old_field='value') # Apply the migration you want to test # Example: app_label 'myapp', migration name '0002_new_field' new_state = migrator.apply_tested_migration(('myapp', '0002_new_field')) # Get the model class from the new state NewMyModel = new_state.apps.get_model('myapp', 'MyModel') # Assertions: Check that the data was migrated correctly new_instance = NewMyModel.objects.get(pk=old_instance.pk) assert hasattr(new_instance, 'some_new_field') # Check for new field # assert new_instance.some_new_field == 'expected_new_value' # Optional: Test rollback # migrator.reset() # assert not NewMyModel.objects.filter(pk=old_instance.pk).exists() # Or check rolled back state