def test_cars_purchase_price():
    v1 = Car(maker='Ford', model='Mustang', year=2005,
             base_price=18000, miles=31000)
    v2 = Car(maker='Ford', model='Mustang', year=2014,
             base_price=31000, miles=11000)

    assert v1.purchase_price() == 21476
    assert v2.purchase_price() == 37156
    def test_cars_purchase_price(self):
        v1 = Car(maker='Ford',
                 model='Mustang',
                 year=2005,
                 base_price=18000,
                 miles=31000)
        v2 = Car(maker='Ford',
                 model='Mustang',
                 year=2014,
                 base_price=31000,
                 miles=11000)

        self.assertEqual(v1.purchase_price(), 21476)
        self.assertEqual(v2.purchase_price(), 37156)