Test-Driven Development (TDD) and Behavior-Driven Development (BDD) in Python! 🐍
Hello, fellow coders! 🖖 Today, we'll take a deep dive into the Python testing waters, exploring two powerful techniques: Test-Driven Development (TDD) and Behavior-Driven Development (BDD). If you're passionate about coding quality and efficiency, this technical journey is for you! Fasten your seatbelts, and let's get started! 🚀
Test-Driven Development (TDD) 🧪
TDD is a software development approach where tests are written before the code. It may sound counter-intuitive at first, but believe me, it's worth the effort!
Let's say we needed to write a simple function in Python to add two numbers. Here's how you would start with a TDD approach using Python's unittest framework.
import unittest
def add(a, b):
# for now we'll keep this implementation empty
pass
class TestAddFunction(unittest.TestCase):
def test_add(self):
self.assertEqual(add(1, 2), 3)
if __name__ == '__main__':
unittest.main()
When your run this, the test will fail because we've not yet implemented our function. Next, we make the test pass.
def add(a, b):
return a + b
Now when you run the tests, they will pass.
We can then optimise or refactor if necessary.
Behavior-Driven Development (BDD)
BDD is a subset of TDD. It presents a more human-friendly approach to writing tests and defining functionality. Instead of focusing on how the functions of the software are implementing, BDD focuses on the actual behaviour of the system.
We'll use the behave Python package for BDD. First, let's define our feature and the behaviour encompassing that feature.
Feature: Addition
As a user of the calculator app
I want to add numbers
So that I can know their sum
Scenario: Add two numbers
Given I have number 5
And I have number 6
When I add them
Then I should get 11
Now, corresponding Python functions (step definitions) will be written to handle those statements.
from behave import when, then, given
@given('I have number {num:d}')
def step_have_number(context, num):
context.num = num
@when('I add them')
def step_add(context):
context.result = context.num_1 + context.num_2
@then('I should get {result:d}')
def step_result(context, result):
assert context.result == result
Thus, TDD and BDD both help in delivering high-quality and bug-free code. Happy coding! 😃
References:
Please note, technology evolves quickly so the reference links may be outdated.
