Testing View Models
Unit test presentation logic in isolation.
Why Test ViewModels?
The ViewModel holds your presentation logic, making it the most valuable layer to unit test. Because it has no UIKit or SwiftUI dependency, you can test it in isolation, fast and deterministically.
Testable by Design
A well-built ViewModel takes its dependencies through its initializer. This lets tests substitute fakes.
final class WeatherViewModel: ObservableObject {
@Published var temperatureText = ""
private let service: WeatherService
init(service: WeatherService) {
self.service = service
}
}All lessons in this course
- The MVVM Pattern
- Binding View Models to Views
- The Coordinator Pattern
- Testing View Models