Unitttest, no test result

anybody help me why cannt see output result of test. Enclosed module code and test file. Thanks a lot and can anybody help me good textbook for python testing for beginners.

#**calculate.py** : #this should be module file



enter code here



class Calculate(object):
  def add(self, x, y):
   return x + y

if __name__ == '__main__':
  calc = Calculate()
  result = calc.add(2, 2)
  print result

#**calculate_test.py**  : #this is test file

import unittest
from app.calculate import Calculate  #this is maybe the problem


class TestCalculate(unittest.TestCase):
  def setUp(self):
    self.calc = Calculate()
    def test_add_method_returns_correct_result(self):
      self.assertEqual("Hellworld", self.calc.add("Hello",
      "World"))