Made a few proxy_models tests use assertRaisesMessage().

        with self.assertRaises(Person.MultipleObjectsReturned):

            StatusPerson.objects.get(id__lt=max_id + 1)

    def test_abc(self):

        """

        All base classes must be non-abstract

        """

        def build_abc():

    def test_abstract_base_with_model_fields(self):

        msg = "Abstract base class containing model fields not permitted for proxy model 'NoAbstract'."

        with self.assertRaisesMessage(TypeError, msg):

            class NoAbstract(Abstract):

                class Meta:

                    proxy = True

        with self.assertRaises(TypeError):

            build_abc()

    @isolate_apps('proxy_models')

    def test_no_cbc(self):

        """

        The proxy must actually have one concrete base class

        """

        def build_no_cbc():

            class TooManyBases(Person, Abstract):

    def test_too_many_concrete_classes(self):

        msg = "Proxy model 'TooManyBases' has more than one non-abstract model base class."

        with self.assertRaisesMessage(TypeError, msg):

            class TooManyBases(User, Person):

                class Meta:

                    proxy = True

        with self.assertRaises(TypeError):

            build_no_cbc()

    @isolate_apps('proxy_models')

    def test_no_base_classes(self):

        def build_no_base_classes():

        msg = "Proxy model 'NoBaseClasses' has no non-abstract model base class."

        with self.assertRaisesMessage(TypeError, msg):

            class NoBaseClasses(models.Model):

                class Meta:

                    proxy = True

        with self.assertRaises(TypeError):

            build_no_base_classes()

    @isolate_apps('proxy_models')

    def test_new_fields(self):