class Car:
    def __init__(self, make="", model="", fuel_consumption=0, fuel_capacity=0):
        self.__make = make
        self.__model = model
        self.__fuel_consumption = fuel_capacity
        self.__fuel_capacity = fuel_capacity
        self.__fuel_amount = 0

    @property
    def make(self):
        return self.__make

    @make.setter
    def make(self, new_value):
        if not new_value:
            raise Exception("Make cannot be null or empty!")
        self.__make = new_value

    @property
    def model(self):
        return self.__model

    @model.setter
    def model(self, new_value):
        if not new_value:
            raise Exception("Model cannot be null or empty!")
        self.__model = new_value

    @property
    def fuel_consumption(self):
        return self.__fuel_consumption

    @fuel_consumption.setter
    def fuel_consumption(self, new_value):
        if new_value <= 0:
            raise Exception("Fuel consumption cannot be zero or negative!")
        self.__fuel_consumption = new_value

    @property
    def fuel_capacity(self):
        return self.__fuel_capacity

    @fuel_capacity.setter
    def fuel_capacity(self, new_value):
        if new_value <= 0:
            raise Exception("Fuel capacity cannot be zero or negative!")
        self.__fuel_capacity = new_value

    @property
    def fuel_amount(self):
        return self.__fuel_amount

    @fuel_amount.setter
    def fuel_amount(self, new_value):
        if new_value < 0:
            raise Exception("Fuel amount cannot be negative!")
        self.__fuel_amount = new_value

    def refuel(self, fuel):
        if fuel <= 0:
            raise Exception("Fuel amount cannot be zero or negative!")
        self.__fuel_amount += fuel
        if self.__fuel_amount > self.__fuel_capacity:
            self.__fuel_amount = self.__fuel_capacity

    def drive(self, distance):
        needed = (distance / 100) * self.__fuel_consumption

        if needed > self.__fuel_amount:
            raise Exception("You don't have enough fuel to drive!")

        self.__fuel_amount -= needed

import unittest


class Tests(unittest.TestCase):
    def test_constr(self):
        car = Car('', "Audi", 69, 420)
        self.assertEqual(car.make, '')
        self.assertEqual(car.model, 'Audi')
        self.assertEqual(car.fuel_consumption, 69)
        self.assertEqual(car.fuel_capacity, 420)

    def test_constr_should_break_on_make(self):
        car = Car()
        with self.assertRaises(Exception):
            car.make = None

    def test_constr_should_break_on_model(self):
        car = Car()
        with self.assertRaises(Exception):
            car.model = None

    def test_constr_should_break_on_cons_negative(self):
        car = Car()
        with self.assertRaises(Exception):
            car.fuel_consumption = -2

    def test_constr_should_break_on_cap_negative(self):
        car = Car()
        with self.assertRaises(Exception):
            car.fuel_capacity = -2

    def test_constr_should_break_on_cons_zero(self):
        car = Car()
        with self.assertRaises(Exception):
            car.fuel_consumption = 0

    def test_constr_should_break_on_cap_zero(self):
        car = Car()
        with self.assertRaises(Exception):
            car.fuel_capacity = 0

    def test_constr_should_break_on_amount_negative(self):
        car = Car()
        with self.assertRaises(Exception):
            car.fuel_amount = -2

    def test_refuel_working(self):
        car = Car('', "Audi", 69, 420)
        car.refuel(2)

    def test_refuel_fuel_zero(self):
        car = Car('', "Audi", 69, 420)
        with self.assertRaises(Exception):
            car.refuel(0)

    def test_refuel_fuel_negative(self):
        car = Car('', "Audi", 69, 420)
        with self.assertRaises(Exception):
            car.refuel(-2)

    def test_drive_working(self):
        car = Car('', "Audi", 69, 420)
        car.fuel_amount = 100
        car.drive(100)
        self.assertEqual(car.fuel_amount, 31)

    def test_drive_error(self):
        car = Car('', "Audi", 69, 420)
        with self.assertRaises(Exception):
            car.drive(50)

if __name__ == '__main__':
    unittest.main()