choice.py

import random

GOAT = 0
CAR = 1

class Door:
    def __init__(self, index):
        self.index = index
        self.gift = GOAT

    def putCar(self):
        self.gift = CAR

    def hasCar(self):
        return self.gift == CAR
    
        
class Game:
    def __init__(self):
        self.doors = [Door(0), Door(1), Door(2)]
        self.doors[random.randint(0,2)].putCar()

    def choice(self):
        self.choice = random.randint(0,2)
#        print "Choice: ", self.choice

    def didWon(self):
        return self.doors[self.choice].gift == CAR
    
    def eliminateGoatThenChoiceAnotherDoor(self):
        remainingDoors = self.doors[:]
        del remainingDoors[self.choice]
        if remainingDoors[0].hasCar():
            del remainingDoors[1]
        else:
            del remainingDoors[0]

        self.choice = remainingDoors[0].index
        

if __name__ == '__main__':

    winCountForStick = 0
    COUNT = 1000
    for i in range(COUNT):
        g = Game()
        g.choice()
        if g.didWon():
            winCountForStick = winCountForStick + 1
    
    winCountForSwap = 0
    for i in range(COUNT):
        g = Game()
        g.choice()
        g.eliminateGoatThenChoiceAnotherDoor()
        if g.didWon():
            winCountForSwap = winCountForSwap + 1

    print "Did %d games..." % (COUNT)
    print "win for stick ", winCountForStick
    print "win for swap", winCountForSwap

choice_test.py

import unittest
from choice import *

class GameInitTest(unittest.TestCase):
    def testInit(self):
        g = Game()
        self.assertEqual(3, len(g.doors))
        
    def testChoice(self):
        for x in range(10):
            g = Game()
            g.choice()
            self.assertTrue(g.choice >= 0)
            self.assertTrue(g.choice <= 2)

    def testDidWon(self):
        g = Game()
        g.doors[0].gift = CAR
        g.choice = 0
        
#        g.eliminateGoat()
        self.assertTrue(g.didWon())

    def testEliminateGoatAndChoiceAnotherDoor1(self):
        g = Game()
        g.doors = [Door(0), Door(1), Door(2)]
        g.doors[1].putCar()
        g.choice = 0
        g.eliminateGoatThenChoiceAnotherDoor()
        
        self.assertEqual(1, g.choice)

    def testEliminateGoatAndChoiceAnotherDoor2(self):
        g = Game()
        g.doors = [Door(0), Door(1), Door(2)]
        g.doors[0].putCar()
        g.choice = 0
        g.eliminateGoatThenChoiceAnotherDoor()
        
        self.assertEqual(2, g.choice)

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