Unit

Testing

with

Python

Materials available at: http://bit.ly/CUUnitTesting

Overview

  • What is unit testing
  • Why do unit testing
  • Python crash course
  • How to do unit testing in Python

What is Unit Testing?

  • Goal: Isolate a unit of code and test its' correctness
  • Test it through using it in a "test" method and by asserting some behavior to be true
  • By testing every unit you can ensure that the whole program is correct
  • These tests can be automated or manual
  • Tests are executed often to ensure the code is working

Good Unit Tests

  • Short and sweet
  • Quick execution
  • One desired functionality per test
  • Cover all of the code
  • Contain good code
    • Including readability and best practices
  • Have explicit method names

Why bother with Unit Testing?

  • You can ensure that future changes do not break the existing functionality
  • Easier to find where the code is wrong
  • If you write the unit tests first it often simplifies development, this is called Test Driven Development

Python Crash Course

REPL

Read - Evaluate - Print - Loop

Python 3.7.2+ (default, Feb 27 2019, 15:41:59) 
[GCC 8.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, world!")
Hello, world!

Functions

def foo(argument_1, argument_2):
    return argument_1 + argument_2


>>> foo(1, 2)
3

Conditionals

if number == 1:
    print("one")
elif number == 2:
    print("two")
elif number == 3:
    print("three")

Classes

class Jody:
    def __init__(self, love_for_gryffn):
        self.has_dog = True
        self.love_for_dog = love_for_gryffn

    def grade_homework(self, grade):
        if grade > 90:
            return "A"
        else:
            return "F"

>>> strausser = Jody(10000)
>>> strausser.grade_homework(101)
"A"

Imports

import math

>>> print(math.log(10))
2.302585092994046

How to Unit Test in Python 3

  • UnitTest
  • DocTest
  • Quick and dirty way of doing unit tests
  • Searches for REPL-like blocks in the comment at the top of a function
  • ut-doctest.py
  • "Classic" way of doing unit tests
  • Create a new class containing functions that do the testsĀ 
  • ut-unittest.py

Additional Resources

Unit Testing with Python

By Alex Day

Unit Testing with Python

Introduction to unit testing with python in mind

  • 85
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