text: import datetime
  import os
  import pickle
  import subprocess
  import sys
  import warnings
  
  from django.core.files.temp import NamedTemporaryFile
  from django.db import DJANGO_VERSION_PICKLE_KEY, models
  from django.test import TestCase
  from django.utils.encoding import force_text
  from django.utils.version import get_major_version, get_version
  
  from .models import Article
  
  
  class ModelPickleTestCase(TestCase):
      def test_missing_django_version_unpickling(self):
          """
          #21430 -- Verifies a warning is raised for models that are
          unpickled without a Django version
          """
          class MissingDjangoVersion(models.Model):
              title = models.CharField(max_length=10)
  
              def __reduce__(self):
                  reduce_list = super(MissingDjangoVersion, self).__reduce__()
                  data = reduce_list[-1]
                  del data[DJANGO_VERSION_PICKLE_KEY]
                  return reduce_list
  
          p = MissingDjangoVersion(title="FooBar")
          with warnings.catch_warnings(record=True) as recorded:
              pickle.loads(pickle.dumps(p))
              msg = force_text(recorded.pop().message)
              self.assertEqual(msg,
                  "Pickled model instance's Django version is not specified.")
  
      def test_unsupported_unpickle(self):
          """
          #21430 -- Verifies a warning is raised for models that are
          unpickled with a different Django version than the current
          """
          class DifferentDjangoVersion(models.Model):
              title = models.CharField(max_length=10)
  
              def __reduce__(self):
                  reduce_list = super(DifferentDjangoVersion, self).__reduce__()
                  data = reduce_list[-1]
                  data[DJANGO_VERSION_PICKLE_KEY] = str(float(get_major_version()) - 0.1)
                  return reduce_list
  
          p = DifferentDjangoVersion(title="FooBar")
          with warnings.catch_warnings(record=True) as recorded:
              pickle.loads(pickle.dumps(p))
              msg = force_text(recorded.pop().message)
              self.assertEqual(msg,
                  "Pickled model instance's Django version %s does not "
                  "match the current version %s."
                  % (str(float(get_major_version()) - 0.1), get_version()))
  
      def test_unpickling_when_appregistrynotready(self):
          """
          #24007 -- Verifies that a pickled model can be unpickled without having
          to manually setup the apps registry beforehand.
          """
          script_template = """#!/usr/bin/env python
  import pickle
  
  from django.conf import settings
  
  data = %r
  
  settings.configure(DEBUG=False, INSTALLED_APPS=('model_regress',), SECRET_KEY = "blah")
  article = pickle.loads(data)
  print(article.headline)"""
          a = Article.objects.create(
              headline="Some object",
              pub_date=datetime.datetime.now(),
              article_text="This is an article",
          )
  
          with NamedTemporaryFile(mode='w+', suffix=".py") as script:
              script.write(script_template % pickle.dumps(a))
              script.flush()
              pythonpath = [os.path.dirname(script.name)] + sys.path
              env = {
                  # Needed to run test outside of tests directory
                  str('PYTHONPATH'): os.pathsep.join(pythonpath),
                  # Needed on Windows because http://bugs.python.org/issue8557
                  str('PATH'): os.environ['PATH'],
                  str('TMPDIR'): os.environ['TMPDIR'],
                  str('LANG'): os.environ.get('LANG', ''),
              }
              if 'SYSTEMROOT' in os.environ:  # Windows http://bugs.python.org/issue20614
                  env[str('SYSTEMROOT')] = os.environ['SYSTEMROOT']
              try:
                  result = subprocess.check_output([sys.executable, script.name], env=env)
              except subprocess.CalledProcessError:
                  self.fail("Unable to reload model pickled data")
          self.assertEqual(result.strip().decode(), "Some object")
  