#!/usr/bin/python

# Find the sum of all the multiples of 3 or 5 below 1000.

import unittest
from multiprocessing import Pool

class main_test(unittest.TestCase):
    def test_multisum(self):
        self.assertEqual(multisum(3, 10), 18) # 3,6,9
        self.assertEqual(multisum(5, 10), 5)  # 5
        self.assertEqual((multisum(3, 10) + 
                          multisum(5, 10)), 23) # 3,5,6,9

# the solver
def multisum(multiple, limit):
    value = 0
    result = [ ]
    while (value + multiple) < limit: # preflight check
        value += multiple
        result.append(value)
    return result

if __name__ == "__main__":
    #unittest.main()
    pool = Pool(processes=2)

    # Setting up the processes and process pool.
    threes = pool.apply_async(multisum, (3, 1000))
    fives = pool.apply_async(multisum, (5, 1000))
    
    # because each process is running without a shared state, it's
    # required to find a union of the two results. "multiples of 3 OR
    # 5 below 1000"

    result_set = set.union(set(threes.get()), set(fives.get()))
    
    print sum(result_set)