Unit tests promise the developers to allow refactoring, which is changing the implementation without modifying the behaviour of the code. Unfortunately, this often turns out to be the false promise in complex enough systems. The article will help you structure the tests to regain this benefit.…
TDD is not an easy concept to begin with. Even though writing a unit-test is a rather obvious task, many developers restrain themselves from trying to build a new feature in a test-first approach. The article shows how to start doing TDD on a real-life usage scenario.…
Separating decisions and calculations from side-effects is a key to successful unit-testing. The article shows example of refactoring the code to do so.…
Functional programming might be a strange beast for Cocoa veterans. This tutorial helps to understand how & why you should compose functions together.…
UICollectionView is one of the most flexible and powerful, but also mysterious and tricky components in UIKit toolbelt. I've learned it the hard way when trying to build a simple, Facebook-like feed. Here're my lessons learned.…
Imperative shell, functional core is one of the concepts that influenced my programming career the most. It perfectly formulates how to write clean, easily testable code and always keeps you wondering whether you did enough to extract the functional pieces. During my preparations for the Mobile Warsaw #62 talk I…
Recently, I came across a couple of real-world examples that illustrate functional programming usage in Swift. All those examples have a single thing in common - they have been initially written in an imperative manner, which made them harder to read and extend. The article provides an in-depth description of…
As you might already know, I deliberately chose not to use storyboards for my Swift code. Instead, I build all of the views programmatically and inject them through initializers into suitable controllers. Although this approach works really nice, it has drawbacks when it comes to unit testing. Imagine having a…
So you already have an app and you are trying to engage users even more... What is a better way to do that than using one of the coolest iOS 10 features - iMessage integration? This Tuesday Apple rolled out iOS 10 together with Messages framework. It provides building blocks…
UITableView is truly a heart of iOS user interface. It does not matter whether you are changing settings, going through unread emails or sending messages. Provided that you have used your iOS device recently, it is almost certain that you have stumbled upon a table view. Rendering a table with…