frontend/setup_test_environment.py

import tempfile, shutil, os
from django.core import management
from django.conf import settings
import common

# we need to set DATABASE_ENGINE now, at import time, before the Django database
# system gets initialized.
# django.conf.settings.LazySettings is buggy and requires us to get something
# from it before we set stuff on it.
getattr(settings, 'DATABASE_ENGINE')
settings.DATABASE_ENGINE = 'sqlite3'
settings.DATABASE_NAME = ':memory:'

from django.db import connection
from autotest_lib.frontend.afe import readonly_connection

def set_test_database(database):
    settings.DATABASE_NAME = database
    destroy_test_database()


def backup_test_database():
    temp_fd, backup_path = tempfile.mkstemp(suffix='.test_db_backup')
    os.close(temp_fd)
    shutil.copyfile(settings.DATABASE_NAME, backup_path)
    return backup_path


def restore_test_database(backup_path):
    connection.close()
    shutil.copyfile(backup_path, settings.DATABASE_NAME)


def cleanup_database_backup(backup_path):
    os.remove(backup_path)


def run_syncdb(verbosity=0):
    management.call_command('syncdb', verbosity=verbosity, interactive=False)


def destroy_test_database():
    connection.close()
    # Django brilliantly ignores close() requests on in-memory DBs to keep us
    # naive users from accidentally destroying data.  So reach in and close
    # the real connection ourselves.
    # Note this depends on Django internals and will likely need to be changed
    # when we move to Django 1.x.
    real_connection = connection.connection
    if real_connection is not None:
        real_connection.close()
        connection.connection = None


def set_up():
    run_syncdb()
    readonly_connection.ReadOnlyConnection.set_globally_disabled(True)


def tear_down():
    readonly_connection.ReadOnlyConnection.set_globally_disabled(False)
    destroy_test_database()