test_migrations.py 文件源码

def test_alter_field(self):
        project_state = self.set_up_test_model()
        operation = migrations.AlterField('Pony', 'pink', models.IntegerField(null=True))
        new_state = project_state.clone()
        operation.state_forwards('tests', new_state)
        self.assertColumnNotNull('tests_pony', 'pink')
        with connection.schema_editor() as editor:
            operation.database_forwards('tests', editor, project_state, new_state)
        self.assertColumnNull('tests_pony', 'pink')
        with connection.schema_editor() as editor:
            operation.database_backwards('tests', editor, new_state, project_state)
        self.assertColumnNotNull('tests_pony', 'pink')