cart_2.apply_voucher(voucher.code)

        # After the reservation duration

        # user 2 should be able to apply voucher

        self.add_timedelta(rego.Voucher.RESERVATION_DURATION * 2)

        cart_2.apply_voucher(voucher.code)

        # After the reservation duration, even though the voucher has applied,

        # it exceeds the number of vouchers available.

        self.add_timedelta(rego.Voucher.RESERVATION_DURATION * 2)

        with self.assertRaises(ValidationError):

            cart_1.validate_cart()

    def test_voucher_can_only_be_applied_once_across_multiple_carts(self):

        voucher = self.new_voucher(limit=2)

        current_cart = TestingCartController.for_user(self.USER_1)

        current_cart.apply_voucher(voucher.code)

        current_cart = TestingCartController.for_user(self.USER_1)

        with self.assertRaises(ValidationError):

            current_cart.apply_voucher(voucher.code)