test_migrations.py 文件源码

def test_run_python(self):
        """
        Because this can run arbitrary python code, we can't know
        which parts of it need to run against each schema, and which
        parts run against the public schema.

        We could hack into any generated SQL, and inspect it, looking
        for table names, attempting to push data to the correct
        schemata (including executing the SQL multiple times if
        necessary).

        Maybe we could fuck with the models generated by project_state.render(),
        and make their generated SQL do what we need it to do. Although, it looks
        like Pony.objects is a normal models.Manager class.
        """
        project_state = self.set_up_test_model()

        def forwards(models, schema_editor):
            Pony = models.get_model('tests', 'Pony')
            Pony.objects.create(pink=1, weight=3.55)
            Pony.objects.create(weight=5)

        def backwards(models, schema_editor):
            Pony = models.get_model('tests', 'Pony')
            Pony.objects.filter(pink=1, weight=3.55).delete()
            Pony.objects.filter(weight=5).delete()

        operation = migrations.RunPython(forwards, reverse_code=backwards)
        new_state = project_state.clone()
        operation.state_forwards('tests', new_state)

        Pony = project_state.apps.get_model('tests', 'Pony')

        @all_schemata
        def pony_count(count, **kwargs):
            found = Pony.objects.count()
            self.assertEqual(
                count,
                found,
                'Incorrect number of Ponies found in schema '
                '{schema}: expected {0}, found {1}'.format(count, found, **kwargs)
            )

        pony_count(0)

        with connection.schema_editor() as editor:
            operation.database_forwards('tests', editor, project_state, new_state)

        pony_count(2)

        with connection.schema_editor() as editor:
            operation.database_backwards('tests', editor, new_state, project_state)

        pony_count(0)