Unit Testing a Complex View Model

Mastering MVVM with SwiftUI

In the previous episode, we wrote unit tests for a simple view model, the AddLocationCellViewModel struct. In this episode, we take it up a notch and write unit tests for a complex view model. We take the AddLocationViewModel class as an example.

in Model-View-ViewModel

Unit Testing a Simple View Model

Mastering MVVM with SwiftUI

One of the key benefits of the Model-View-ViewModel pattern is improved testability. It isn't possible to write unit tests for the SwiftUI views we created, but we can unit test the view models that drive those views. The good news is that writing unit tests for a well-designed view model isn't difficult.

in Model-View-ViewModel

Why Gut Health Matters as a Developer

As developers, we spend long hours in front of screens, often neglecting our health. I’ve learned that gut health is a game-changer for focus, energy, and productivity. Eating whole foods and tracking fiber diversity with Plant Power has made a real difference for me.

in Announcements

How to Set Up In-App Purchases with RevenueCat

Offering a subscription product in your application involves more than integrating with Apple's StoreKit framework. You need to set up subscription products in App Store Connect, keep track of the user's subscription status, and restrict access to the content or features that are exclusive to subscribers. Things get even more complicated if your application offers multiple tiers or is available on multiple platforms.

in StoreKit

Injecting Dependencies with Swinject

Mastering MVVM with SwiftUI

We hit a roadblock in the previous episode. The CurrentConditionsViewModel struct needs access to a Store object, but it is tedious to pass a Store object from one view model to the next. In this episode, we use a dependency injection library, Swinject, to make this much less of a problem.

in Model-View-ViewModel

Deleting Locations

Mastering MVVM with SwiftUI

The last feature we need to add is the ability to delete locations. The changes we need to make are small, but there is a problem we need to address. Let's start by adding a button to the CurrentConditionsView.

in Model-View-ViewModel

Defining the States of the Location View

Mastering MVVM with SwiftUI

The LocationView is always in one of two states, fetching weather data or displaying weather data. It is the LocationView itself that implicitly defines these states and that is limiting. Not only is it limiting, we cannot write unit tests for the states of the LocationView. In this episode, I show you a solution that is testable and extensible.

in Model-View-ViewModel

Refactoring the Location View Model

Mastering MVVM with SwiftUI

The LocationView still displays stub data. That is something we change in this episode. The LocationViewModel struct is responsible for fetching the weather data the LocationView displays. It uses that weather data to create view models for the CurrentConditionsView and the ForecastView.

in Model-View-ViewModel

Refactoring the Forecast View Model

Mastering MVVM with SwiftUI

In this episode, we refactor the ForecastViewModel struct and the ForecastCellViewModel struct. The ForecastViewModel struct drives the ForecastView, the bottom section of the LocationView. Let's get to work.

in Model-View-ViewModel

Refactoring the Current Conditions View Model

Mastering MVVM with SwiftUI

In this episode, we refactor the CurrentConditionsViewModel struct. Remember that the CurrentConditionsViewModel struct drives the CurrentConditionsView, the top section of the LocationView. The changes we need to make are small.

in Model-View-ViewModel

Protecting Secrets with a Proxy Server

Most of the services your application interacts with require authentication. Authentication through a secret, an API key or a client secret, is a commonly used method. Your application includes the secret in the request it sends to the service. That is only possible if your application has access to the secret at runtime.

in Security

Avoiding Code Duplication

Mastering MVVM with SwiftUI

In the previous episode, we used the MeasurementFormatter class to format the raw values the Clear Sky API returns. This is convenient and we use the MeasurementFormatter class several more times in the next few episodes. In this episode, we create an elegant API that wraps around the MeasurementFormatter API to avoid code duplication.

in Model-View-ViewModel