import unittest
def doubler(func):
    #doubles all arguments
    def inner(*args):
        double_args = [2*arg for arg in args]
        return func(*double_args)
    return inner
        
class TestDoubler(unittest.TestCase):
    def testDoubling(self):
        x = 2
        y = 3
        def mock_add(a,b):
            self.assertEquals((a,b),(2 * x, 2 * y))
            return 2 * (a + b)
        #decorate
        mock_adder = doubler(mock_add)
        mock_adder(2,3)