'django.db.models shouldn\'t be imported if unused.'

def test_models_import_omitted(self):

    migration = type('Migration', (migrations.Migration,), {'operations': [migrations.AlterModelOptions(name='model', options={'verbose_name': 'model', 'verbose_name_plural': 'models'})]})
    writer = MigrationWriter(migration)
    output = writer.as_string()
    self.assertIn('from    django.db    import    migrations\n', output)
