Archives For TDD

iPhreaks is a terrific podcast done as a panel discussion. The panel often brings strong experience from other platforms. (In fact, iPhreaks is the iOS cousin to the Ruby Rogues panel.) They already discussed TDD in episode 95. Following up on that, I’m honored that they invited me as their guest to talk more about TDD and Testing in episode 116.

iphreaks Continue Reading…

We’ve TDD’d a class that should handle authentication to the Marvel API. It looks good in theory. But how do we know if it really works?

In addition to TDD-ing part of a system, it’s important to get feedback about the system as a whole. So before we go on to write code to request Marvel comic book characters by name, let’s make sure the authentication class works at all.

We’ll do that with an acceptance test.

Acceptance test: Snapping in a jigsaw piece Continue Reading…

If you don’t know what some code should do, you can’t TDD it. A spike solution (a throwaway experiment) gives enough information to begin the TDD process. But now we’re faced with design decisions: What methods do we want? How should they be organized? How should they be accessed?

With Test Driven Development, the surprising answer is: it doesn’t matter that much, because it’s going to change anyway.

Breaking “Analysis Paralysis” with TDD
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The biggest benefit of Test Driven Development is fast feedback. And so one of the best ways to keep your TDD effective is to make sure you get that feedback as fast as you can.

But most iOS folks use their production app delegate when testing. This is a problem.

That’s because when you run your tests, it first fires up your app — which probably does a lot. A bunch of slow stuff. And that’s a bunch of slow stuff we don’t need or want for our tests.

How can we avoid this? Continue Reading…

Using a hammer to drive in a screw. I mean, it works, kind of.

But if you use a tool in a way other than its intended purpose, you’ll be missing its most important benefits.

It’s kind of like that with Test Driven Development.

Is TDD about preventing bugs? That’s more of a side effect than a direct goal.

Is it about making a test suite? Well, kind of. But… no. Not really. Continue Reading…

It’s one thing to say, “Do test driven development.” But practicing TDD requires a set of tricks — you need techniques to enable test driven development in your particular environment. It’s these techniques which I hope to pass on to you through a case study of building an iOS TDD sample app.

The TDD sample app will yield treasures of how-to examples

Treasure Chest” by Tom Garnett, used under CC BY 2.0

I’ve accumulated a treasure chest of TDD ideas over the years. These ideas are often not my own, but are other people’s ideas which I collect and curate. Some are about object-oriented design. Some are about working in Xcode and Objective-C. And some are particular to iOS development. I’ve collected many, and continue to gather new ones.

I’m building this TDD sample app so that you and I can browse through this treasure chest together. You may have tried test driven development and given up on it. Or maybe you’re still trying, but finding it frustratingly slow. The ideas we will explore together will help you break through to make headway in your TDD journey, so that you can experience the freedom and ease that comes from automated testing and clean code. Continue Reading…

The results of my reader survey are in. The #1 request? Case studies of unit testing, with more complex examples. And that got me thinking about the next major direction to take this blog.

When I was first learning Test Driven Development, I didn’t really have any examples to look at. All I had were descriptions of TDD. I stubbornly believed that these descriptions showed a more effective way of programming, so I fought my way there through the School of Hard Knocks.

But you shouldn’t have to do the same. Continue Reading…

AppCode is an alternative IDE for Objective-C development. When it comes to test driven development, it’s superior to Xcode. But that’s not all. Check out the “inside-out” coding style it makes possible.

In general, AppCode lets me focus more quickly on semantics and less on fiddling with source code.

This screencast shows some of the templates I use, which you can get here.


Question: What other AppCode tricks do you like? Leave a comment below.

Remember my iOS Model-View-Controller TDD screencast? Eric Baker took it a few extra steps with his own follow-up screencast, demonstrating:

There’s a lot of interesting stuff here. But I also want to acknowledge that this screencast changed my mind about dot notation. Yes, really!

What are your thoughts about ReactiveCocoa, Kiwi, or AppCode? Leave a comment below.

The UIViewController TDD screencast ended with all the code in the view controller. Unfortunately, this is where many iOS programmers leave things! Let’s TDD our way to something better…

In part 2, we pick up from there and TDD to extract a model class, which the controller observes. You’ll see it evolve into true Model-View-Controller, driven by unit tests.

In particular, you’ll see how to TDD:

  • a model that posts notifications when it changes, and
  • a controller that observes those notifications.

Continue Reading…