At PSS we have written a number of technical blog series and posts, linked below. Each gives you a window into our approach to software development and architecture. We also have more articles on our main medium website. Architecture The Unit Testing Diet A two-part series about scaling unit tests while enabling refactoring on mobile…

Quick framework’s newest command makes BDD tests even more DRY — How do you write effective unit tests for an API call in Swift? You’ve probably seen or written the following code dozens (hundreds?) of times: This test approach is fine, but what happens when your call should be invoked only after prior operations have been completed by the user? …

Improving the Swift Errors or Kotlin Throwables of your APIs — Note: we have a newer article on error rendering with declarative UIs, written in 2023 that you can read here. An API design refresher If you’ve written any kind of mobile app, there’s a 99% chance you’re also going to be calling a remote network API. Reactive patterns are a popular approach, and reactive…

Pitfalls when chaining reactive streams using Combine on iOS — Our mobile client has invested heavily in reactive programming. In addition to providing cleaner design patterns for us to interact with asynchronous services (network API calls, disk reads, etc), reactive programming enables us to write near-identical code on both Android and iOS. Note the use of the term near-identical. There…

BehaviorSubjects are a common primitive in RxJava — an effective substitute for properties on objects that provide reactive semantics on a mutated value. …

One of the key concepts of Reactive APIs is the ability to control, and switch, the active thread of execution. Methods like subscribeOn and observeOn in RxJava, or subscribe(on or receive(on in Combine, or start(on and observe(on in ReactiveSwift, are core building blocks when constructing any reactive stream. In this…

Classes you’ll want and need when coding that API — It’s time to see what a Clean API endpoint actually looks like in practice. Per our earlier blog post about the Endpoint Responsibility Checklist, we know that the steps in an execution path in response to an HTTP request are: 🔵Receive→🟢Validate→🔴Validate→🟢Enqueue→🟢Respond Note the line above — we are going to…

What API frameworks all (should) do — What does an API endpoint do? In our series on Clean API Architecture, we have explained how there are multiple layers involved in responding to an HTTP request. …

When code is executed, how does it respond? — In this series we are exploring patterns for web API architecture. In order to build our case, we must first take a detour to explore common patterns of code execution whenever you call a remote API endpoint. Computation 101