#321 unittest – unit testing framework in python

calculator.py

#A simple calculator
class Calculator:
  #empty constructor
  def __init__(self):
    pass
  #add method - given two numbers, return the addition
  def add(self, x1, x2):
    return x1 + x2
  #multiply method - given two numbers, return the 
  #multiplication of the two
  def multiply(self, x1, x2):
    return x1 * x2
  #subtract method - given two numbers, return the value
  #of first value minus the second
  def subtract(self, x1, x2):
    return x1 - x2
  #divide method - given two numbers, return the value
  #of first value divided by the second
  def divide(self, x1, x2):
    if x2 != 0:
      return x1/x2

test_calculator.py

import unittest
from calculator import Calculator
#Test cases to test Calulator methods
#You always create  a child class derived from unittest.TestCase
class TestCalculator(unittest.TestCase):
  #setUp method is overridden from the parent class TestCase
  def setUp(self):
    self.calculator = Calculator()
  #Each test method starts with the keyword test_
  def test_add(self):
    self.assertEqual(self.calculator.add(4,7), 11)
  def test_add2(self):
    self.assertEqual(self.calculator.add(7,4), 11)
  def test_subtract(self):
    self.assertEqual(self.calculator.subtract(10,5), 5)
  def test_multiply(self):
    self.assertEqual(self.calculator.multiply(3,7), 21)
  def test_divide(self):
    self.assertEqual(self.calculator.divide(10,2), 5)
# Executing the tests in the above test case class
if __name__ == "__main__":
  unittest.main()

Output:

</pre>
Ran 5 tests in 0.001s

OK
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