A presentation at c’t webdev in in Cologne, Germany by Daniela Valero
Mental hacks to master Unit Testing
• The vicious circle Agenda • Break the loop • Getting the time • Mental Hacks (Using the time wisely)
The vicious circle
What today is… …is Tomorrow No time to Crazy regressions unit test & unexpected bugs
What today is… …is Tomorrow Lack of No meaningful practice unit tests
Break the loop
Getting the time
Selling points ARGUMENTS to convert your boss a Unit Testing fan %
Argument to get time What is unit testing …in non techies words
Argument to get time: Pyramid of testing: UI - Service - Unit
Argument to get time The goal of unit testing is to sustain project growth by preventing software entropy
Argument to get time Solid unit tested code increases time to market by minimizing regressions
Argument to get time Writing unit tests today reduces the cost of the feature of tomorrow
Once you get the time… you need to be aware of…
Time stealers SNEAKY things that can fill your time
Time stealers Time running unit tests
Time stealers Time spent reading unit tests
Time stealers Time spent rewriting tests
Time stealers Time dealing with false alarms
Writing the cool test
Step back Set the concepts STRAIGHT
Concepts to get straight Test Accuracy …what meaningful or cool actually stand for
Concepts to get straight Functionality Test Result Correct Pass Fail ! # False Positive Resistance to Refactoring Broken ” False Negative ! Protection against regressions
Concepts to get straight Pillars of Unit Testing
Concepts to get straight Resistance to refactoring Focus Focus Maintainability Protection against regressions Choose Choose Fast Feedback
Mental hacks WRITING the test that helps
Mental hack: Black box testing Test WHAT happens, not HOW it happens
Mental hack: Anti Example
Mental hack: Example
Mental hack: Test what matters Focus on: important or complex code
Mental hack: Test what matters Shopping Cart in E-Commerce Validations in Form Heavy pages
Mental hack: Test what matters Complex / Important Complex or Important Over complicated Test Split No. of Dependencies or side effects Trivial Controllers Ignore Optional
Mental hacks The STRUCTURE of the test that helps
Mental Hack: Test Anatomy Given — When — Then
Mental Hack: Your test shall tell 2 Function — Scenario — Expected behavior
Mental Hack: Anti Example
Mental Hack: Example
Mental Hack: Your test aint’ wrong… 3 …your code is!
4 Mental Hack: Read the docs Get familiarized with your testing framework API
• The vicious circle Recap • Break the loop • Getting the time • Mental Hacks (Using the time wisely)
Spoiler alerts • WANT: a more scalable and flexible codebase • PRICE: the beginner struggle, but keep going • NEW YOU: you’ll write more testable code from start
Thank You Where to find me… DanielaValero.com
There is a big wall that separates good developers from writing unit tests. The wall is made of misconceptions. And this make us think that they are hard to write, we don’t have time for that or only the profis do them. What if there was a path you could use to go through that wall? Or what if the wall was made of air? During this talk, I want to give you a set of mental hacks to use right away. Using these strategies, can get you not only writing solid unit tests, but also having the time for them.
for free. You
can too.