Testing SwiftUI

Write unit tests for view models and UI tests for SwiftUI views to validate behavior and flows.

Unit Test a ViewModel

Place business logic in a ViewModel and verify it using XCTestCase.

Syntax:

• final class MyTests: XCTestCase { ... }
• assertions like XCTAssertEqual, XCTAssertTrue

import SwiftUI
import Combine

final class CounterViewModel: ObservableObject {
  @Published private(set) var count = 0
  func increment() { count += 1 }
}

struct CounterView: View {
  @StateObject private var vm = CounterViewModel()
  var body: some View {
    VStack(spacing: 12) {
      Text("Count: \(vm.count)")
      Button("Increment") { vm.increment() }
    }
  }
}

import SwiftUI

struct ContentView: View {
  var body: some View { CounterView() }
}

import SwiftUI

@main
struct MyApp: App {
  var body: some Scene { WindowGroup { ContentView() } }
}

import XCTest

final class CounterViewModelTests: XCTestCase {
  func testIncrement() {
    let vm = CounterViewModel()
    vm.increment()
    XCTAssertEqual(vm.count, 1)
  }
}

This example verifies that calling increment() updates the published count.

Prerequisites (UI Testing Target)

• Add a UI Testing Bundle target (File → New → Target → UI Testing Bundle).
• Prefer locating elements by accessibility identifiers rather than visible text.
• Pass launch arguments and environment to control app state for tests (e.g., reset data, use fakes).

UI Test a SwiftUI View

Drive the app with XCUIApplication and locate elements by accessibility.

Syntax:

• let app = XCUIApplication(); app.launch()
• app.buttons["Label"].tap()

import SwiftUI

struct UITestDemo: View {
  @State private var count = 0
  var body: some View {
    VStack(spacing: 12) {
      Text("Count: \(count)").accessibilityIdentifier("countLabel")
      Button("Increment") { count += 1 }
        .accessibilityIdentifier("incrementButton")
    }
  }
}

import SwiftUI

struct ContentView: View {
  var body: some View { UITestDemo() }
}

import SwiftUI

@main
struct MyApp: App {
  init() {
    let args = ProcessInfo.processInfo.arguments
    let env = ProcessInfo.processInfo.environment
    if args.contains("-ui-testing") || env["UITEST_RESET"] == "1" {
      // Reset state, use mock stores/services, disable animations, etc.
      // UIView.setAnimationsEnabled(false) can be used where applicable.
    }
  }
  var body: some Scene { WindowGroup { ContentView() } }
}

import XCTest

final class MyUITests: XCTestCase {
  func testIncrementButton() {
    let app = XCUIApplication()
    app.launchArguments = ["-ui-testing"]
    app.launchEnvironment = ["UITEST_RESET": "1"]
    app.launch()

    let button = app.buttons["incrementButton"]
    XCTAssertTrue(button.waitForExistence(timeout: 2))
    button.tap()

    let label = app.staticTexts["countLabel"]
    XCTAssertTrue(label.waitForExistence(timeout: 2))
    XCTAssertTrue(label.label.contains("Count: 1"))
  }
}

This example launches the app, taps the button, and asserts the label exists via its accessibility identifier.