snapshot

name	snapshot
description	Creates Snapshot Tests for SwiftUI Views using ChallengeSnapshotTestKit. Use when creating visual regression tests for views with DSAsyncImage support.

Skill: Snapshot Tests

Guide for creating Snapshot Tests using ChallengeSnapshotTestKit. Tests only use ChallengeSnapshotTestKit's public API. See the module README for internal details.

References

• Concrete test examples: See references/examples.md

---

Prerequisites

1. ChallengeSnapshotTestKit dependency in snapshot test targets (added automatically by Tuist)
2. DSAsyncImage component (replaces AsyncImage)
3. ImageLoaderMock in CoreMocks
4. Test image in Tests/Shared/Resources/

File Structure

Tests/
├── Snapshots/
│   └── Presentation/
│       └── {Name}/
│           ├── {Name}ViewSnapshotTests.swift
│           └── __Snapshots__/
└── Shared/
    ├── Stubs/
    │   └── {Name}ViewModelStub.swift
    └── Resources/
        └── test-avatar.jpg

---

Test Structure

Uses instance variables pattern for cleaner tests:

struct {Name}ViewSnapshotTests {
    // MARK: - Properties

    private let imageLoader: ImageLoaderMock

    // MARK: - Initialization

    init() {
        UIView.setAnimationsEnabled(false)
        imageLoader = ImageLoaderMock(cachedImage: .stub, asyncImage: .stub)
    }

    // MARK: - Tests

    @Test("Renders loading state correctly")
    func loadingState() {
        // Given
        let viewModel = {Name}ViewModelStub(state: .loading)

        // When
        let view = NavigationStack {
            {Name}View(viewModel: viewModel)
        }
        .imageLoader(imageLoader)

        // Then
        assertSnapshot(of: view, as: .device)
    }
}

---

Key Rules

Test Setup

1. Disable animations: UIView.setAnimationsEnabled(false)
2. Create ImageLoaderMock with test image
3. Inject .imageLoader(imageLoader) on view

View Configuration

1. Wrap in NavigationStack
2. Use .device strategy for full-screen views, .image for components, .component(size:) for components that wrap a Button
3. Apply imageLoader modifier

Naming

• Test file: {Name}ViewSnapshotTests.swift
• Test method: {stateName}State() (e.g., loadingState)
• Test description: @Test("Renders {state} state correctly")
• Snapshots folder: __Snapshots__/{Name}ViewSnapshotTests/

---

Running Tests

First Run (Recording)

xcodebuild test \
  -workspace Challenge.xcworkspace \
  -scheme "Challenge (Dev)" \
  -destination 'platform=iOS Simulator,name=iPhone 17 Pro,OS=26.1'

First run creates references and fails (expected).

Subsequent Runs

Re-run the same command. Snapshots now compare against recorded references.

Regenerate Snapshots

rm -rf Tests/Snapshots/Presentation/{Name}/__Snapshots__
# Run twice: first creates references, second verifies

---

Checklist

Setup (once per feature)

• ChallengeSnapshotTestKit is automatically included by Tuist in snapshot test targets
• Create test image in Tests/Shared/Resources/
• Create ViewModel stub in Tests/Shared/Stubs/
• Create ViewModel protocol

Per View

• Use DSAsyncImage in View
• Create snapshot tests file in Tests/Snapshots/
• All @Test attributes include a description
• Initialize ImageLoaderMock
• Test each state
• Use .device strategy for full-screen views
• Run tests twice (record + verify)