Browse Questions
  • An iOS app moves through states managed by UIApplicationDelegate (UIKit) or @main + scene lifecycle (SwiftUI/iOS 13+).
  • Swift's async/await is directly supported in XCTest — mark your test function as async throws and await the result.
  • Both manage concurrent work, but async/await (introduced in Swift 5.5) is structured and compiler-checked, while GCD is unstructured and callback-based.
  • Snapshot testing captures a reference image of a view and compares future runs against it.

Answer: Snapshot testing captures a reference image of a view and compares future runs against it. Any visual change fails the test, catching unintended UI regressions.

Popular library: swift-snapshot-testing by Point-Free

Code Example:

import SnapshotTesting

class ProfileCardTests: XCTestCase {

    func test_profileCard_defaultState() {
        let view = ProfileCardView(user: .mock())
        let vc = UIHostingController(rootView: view)

        // First run — creates reference snapshot
        // Subsequent runs — compares against saved image
        assertSnapshot(matching: vc, as: .image(on: .iPhone13))
    }

    func test_profileCard_premiumBadge() {
        let view = ProfileCardView(user: .mockPremium())
        assertSnapshot(matching: view, as: .image)
    }
}

Workflow:

  1. Write test → run → reference image saved to __Snapshots__ folder
  2. Commit snapshots to git
  3. Future UI changes fail the test — you review and update the snapshot if intentional