---
title: 'Becoming a better programmer: Test-Driven Development'
date: 2012-02-08
aliases:
- /posts/becoming-a-better-programmer-test-driven-development.html
---



As I’m enjoying programming again (and more so every week), I started to think
consciously again about improving myself as a programmer. After a recommendation
of [breun](http://twitter.com/breun) I started reading [Clean
Code](http://www.pearsonhighered.com/educator/academic/product/1,3110,0132350882,00.html),
which I can definitely recommend.


One of the things I have always felt bad about professionally is not doing
Test-Driven Development. Back when I was programming Haskell a lot I did do a
lot of type-driven development, which overlaps a bit: you write down your types
and then try to implement it. However, in Objective-C the type system isn’t of
much use (compared to Haskell), so I really had to do it: write tests.


Another really big motivation is that I took over a project from another
developer. The project was huge, and there were no tests at all. I ended up
breaking things multiple times without realizing it (and I only found out after
deploying it to the testers). I pledged to myself to do better than that.


Before I set off to write some tests, I had to find a testing framework. There
is a great community wiki on StackOverflow called [iOS Tests/Specs TDD/BDD and
Integration & Acceptance
Testing](http://stackoverflow.com/questions/4114083/ios-tests-specs-tdd-bdd-and-integration-acceptance-testing),
but it’s also a bit overwhelming.


I started out by using the built-in Unit Testing framework that’s provided by
Apple (see: [XCode Unit Testing
Guide](https://developer.apple.com/library/mac/#documentation/DeveloperTools/Conceptual/UnitTesting/)).
However, writing unit tests is quite hard for GUI code. As I wanted to test a
new UIView subclass that I was developing, I had to test things such as tapping
and inspecting other views.


Then I stumbled upon [KIF](https://github.com/square/KIF) (again, after a
recommendation from breun), an open source integration testing framework by
Square. As advertised, it was easy to configure and set up, and I was writing
tests very soon after that. For example, here’s a scenario that tests whether my
view closes, and even when you haven’t used KIF before you can understand
exactly what it does:


``` 
KIFTestScenario *scenario = [KIFTestScenario scenarioWithDescription:@"Test that the picker closes when tapped outside"];

[scenario addStep:[KIFTestStep stepToReset]];
[scenario addStep:[KIFTestStep stepToAppear]];
[scenario addStep:[KIFTestStep stepToWaitForViewWithAccessibilityLabel:pickerAccessibilityLabel]];
[scenario addStep:[KIFTestStep stepToTapViewWithAccessibilityLabel:@"Tap to close"]];
[scenario addStep:[KIFTestStep stepToWaitForAbsenceOfViewWithAccessibilityLabel:pickerAccessibilityLabel]];
```

So far, I’m quite happy with the combination of KIF and the built-in unit
testing. I’ll try to apply it to more of my projects, and probably be a better
programmer because of that. At least when other people will read my code they
can use the tests as documentation to see what the code should do.