Used assertRaisesMessage in managers_regress tests.

    def test_abstract_manager(self):

        # Accessing the manager on an abstract model should

        # raise an attribute error with an appropriate message.

        try:

            AbstractBase3.objects.all()

            self.fail('Should raise an AttributeError')

        except AttributeError as e:

        # This error message isn't ideal, but if the model is abstract and

        # a lot of the class instantiation logic isn't invoked; if the

        # manager is implied, then we don't get a hook to install the

        # error-raising manager.

            self.assertEqual(str(e), "type object 'AbstractBase3' has no attribute 'objects'")

        msg = "type object 'AbstractBase3' has no attribute 'objects'"

        with self.assertRaisesMessage(AttributeError, msg):

            AbstractBase3.objects.all()

    def test_custom_abstract_manager(self):

        # Accessing the manager on an abstract model with an custom

        # manager should raise an attribute error with an appropriate

        # message.

        try:

        msg = "Manager isn't available; AbstractBase2 is abstract"

        with self.assertRaisesMessage(AttributeError, msg):

            AbstractBase2.restricted.all()

            self.fail('Should raise an AttributeError')

        except AttributeError as e:

            self.assertEqual(str(e), "Manager isn't available; AbstractBase2 is abstract")

    def test_explicit_abstract_manager(self):

        # Accessing the manager on an abstract model with an explicit

        # manager should raise an attribute error with an appropriate

        # message.

        try:

        msg = "Manager isn't available; AbstractBase1 is abstract"

        with self.assertRaisesMessage(AttributeError, msg):

            AbstractBase1.objects.all()

            self.fail('Should raise an AttributeError')

        except AttributeError as e:

            self.assertEqual(str(e), "Manager isn't available; AbstractBase1 is abstract")

    @override_settings(TEST_SWAPPABLE_MODEL='managers_regress.Parent')

    def test_swappable_manager(self):