Introduced a mixin for serializing tests.

from django.conf import settings

from django.core import mail

from django.core.exceptions import ImproperlyConfigured, ValidationError

from django.core.files import locks

from django.core.handlers.wsgi import WSGIHandler, get_path_info

from django.core.management import call_command

from django.core.management.color import no_style

    def tearDownClass(cls):

        cls._tearDownClassInternal()

        super(LiveServerTestCase, cls).tearDownClass()

class SerializeMixin(object):

    """

    Mixin to enforce serialization of TestCases that share a common resource.

    Define a common 'lockfile' for each set of TestCases to serialize. This

    file must exist on the filesystem.

    Place it early in the MRO in order to isolate setUpClass / tearDownClass.

    """

    lockfile = None

    @classmethod

    def setUpClass(cls):

        if cls.lockfile is None:

            raise ValueError(

                "{}.lockfile isn't set. Set it to a unique value "

                "in the base class.".format(cls.__name__))

        cls._lockfile = open(cls.lockfile)

        locks.lock(cls._lockfile, locks.LOCK_EX)

        super(SerializeMixin, cls).setUpClass()

    @classmethod

    def tearDownClass(cls):

        super(SerializeMixin, cls).tearDownClass()

        cls._lockfile.close()