Python Unit Test: Basics 1

 When comes to any programming language what i check first is how to write a unit test on it. 

   "Coding is not difficult- Bill Gates" So what is difficult? I would say testing is difficult. Here is a basic example on how to test a small piece of python code.

	def factorial(n):
	if(n==0):
	return 1
	else:
	return n*factorial(n-1)

view raw n_factorial.py hosted with ❤ by GitHub

                The above snippet is a basic recursive program which will return the factorial of a number. Lets see how we can write a basic test case for this. I have my directory structure as follows.

Lets see the contents of n_factorial_tests.py.

	from basics.functions import n_factorial
	import unittest
	class TestNFactorial(unittest.TestCase):
	def testRecursion(self):
	self.assertEqual(n_factorial.factorial(5),120)

view raw n_factorial_tests.py hosted with ❤ by GitHub

• The first line is on importing the program to the test class. 
• Next we are importing unittest : This module provides a rich set of tools for constructing and  running tests.
• While defining a function you can see we have used an object "self". This used to represent an instance of a class. Here it means accessing the contents of unittest.TestCase which is being inherited to this class.
• Now we can access the functions defined unittest.TestCase  module. Because we have inherited that to our test class.
• self.assertEqual(n_factorial.factorial(5),120) : This is the statement where we assert for our expectation vs the actual value.
• If you run this on PyCharm we can see the below.

Finally i wrote a python code and tested it ❤️