Introduction to unittest – Yasoob Khalid

Hello there people. I lately thought that I’ve not written even a single publish about testing in python. Testing is among the most necessary a part of any language. On this publish I’m going to share some details about unittest with you.

So what precisely is unittest? You may need heard about it on StackOverflow or another discussion board. It’s a testing framework for python identical to Junit for Java. It comes pre-installed with python from 2.1. It’s simple to make use of.

Nevertheless there are plenty of different testing frameworks for python on the market as effectively however I shall be specializing in unittest right this moment as it’s the default testing framework for python. So with out losing any time lets get began.

The usual workflow whereas utilizing unittest is:

1. derive your personal class from unittest.TestCase
2. write your checks in features which begin with test_
3. lastly write unittest.most important() on the finish of your file to run the checks

I used to be additionally was once scared by testing. Testing appeared to me as one thing from outer area however now I’ve discovered its significance and it’s important for each programmer to study it.

A easy script

So lets write a easy script which we are able to later take a look at. This script goes to do some math features for us. So right here is the script:

# put it aside as math.py
def multiply(n1, n2):
    return n1 * n2

def add(n1, n2):
    return n1 + n2

So thats our little script. Now lets transfer ahead and write our first take a look at.

Our first take a look at

In order I advised you earlier than that each unittest file accommodates a customized class derived from unittest.TestCase so lets create that:

import unittest
from math import multiply, add

class TestingMath(unittest.TestCase):
    move

if __name__ == "__main__":
    unittest.most important()

In order that was the primary half. Now we have to outline our checks. In unittest there’s a setUp() and tearDown() perform. The setUp() perform is used to arrange the take a look at atmosphere and tearDown() is used to scrub up after a take a look at. We don’t want them as they’re often used when plenty of checks are written for a bigger software program.

The default implementation of setUp() and tearDown() does nothing. So now lets write our first take a look at by modifying our earlier script.

import unittest
from math import multiply, add

class TestingMath(unittest.TestCase):

    def setUp(self):
        move
    def test_multiply(self):
        self.assertEqual( multiply(3,5), 15)

    def test_add(self):
        self.assertEqual( add(3,5), 8)
if __name__ == "__main__":
    unittest.most important()

Now save this file as take a look at.py and run it from the command line and you will note some output like this:

yasoob@yasoob:~/Desktop$ python take a look at.py
..
----------------------------------------------------------------------
Ran 2 checks in 0.000s
OK

Congratulations! You have got written your very first absolutely working take a look at suite in python. Wait! what are these assertEqual() statements there? Let me clarify them. These assert funtions are the backbones of testing in unittest. They verify whether or not the result’s right or not. There are plenty of assert features in unittest. In our case we used assertEqual() which checks whether or not two values are equal or not. We gave 2 parameters to assertEqual() now the job of assertEqual() is to verify whether or not each parameters are equal or not.

Only for reference another assert features are:

assertTrue(x)
assertFalse(x)
assertNotEqual(a, b)
assertIs(a, b)
assertIsNot(a, b)
assertIsNone(x)

Take a look at Discovery

So simply give it some thought for a minute. You have got plenty of take a look at recordsdata and need to run all of them. The one technique which involves thoughts is to manually run all of these recordsdata individually. That is potential when you’ve got 10 recordsdata however what when you’ve got a 100 recordsdata? That’s had been automated take a look at discovery involves rescue. So if I’ve all of my checks in app/checks listing I might merely run:

python -m unittest uncover app/checks

So this command would collect all the take a look at recordsdata within the checks listing and can run them. I hope that was useful.

Furthur

So now you’ve got some concept of how testing works in python. Keep in mind that this was simply an introduction and there’s a complete lot to unittest than this. If you wish to additional improve your information then try the unique python docs about unittest. I’ll cowl different testing frameworks as effectively sooner or later.

I hope you loved this text and do bear in mind this one tip that the perfect time to put in writing checks is whereas creating. In the event you write checks little by little whereas creating then they won’t grow to be a burden and your software shall be rock stable.

Do share your views within the feedback under or be happy to e mail me, or tweet me. Final however not the least observe this weblog and keep tuned for the subsequent publish.