Improved isolation of applied-migrations table in migration tests.

from django.apps import apps

from django.db import connection

from django.db.migrations.recorder import MigrationRecorder

from django.test import TransactionTestCase

from django.test.utils import extend_sys_path

from django.utils.module_loading import module_dir

    available_apps = ["migrations"]

    def tearDown(self):

        # Reset applied-migrations state.

        recorder = MigrationRecorder(connection)

        recorder.migration_qs.filter(app='migrations').delete()

    def get_table_description(self, table):

        with connection.cursor() as cursor:

            return connection.introspection.get_table_description(cursor, table)