generate-unit-tests

name	generate-unit-tests
description	Generate comprehensive unit tests for ProjectX Apple platforms app using Swift Testing (@Test, @Suite, #expect) and XCTest. Covers Swift 6 ViewModels, UseCases, Services, and Mappers with concurrency-first patterns and full branch coverage.

Generate Unit Tests — ProjectX Apple Platforms

Framework

• Swift Testing: @Suite, @Test, #expect, #require, @Test("description")
• XCTest: XCTestCase for UI tests only
• Async: async throws test functions

Workflow

1. Analyze Target

Read the file to test. Identify:

• All public/internal methods
• All code branches (if/switch/guard/do-catch)
• Dependencies (protocols to fake)
• State transitions (for ViewModels)

2. Create Fakes

For each protocol dependency, create a fake:

struct FakeEntityService: EntityServiceProtocol {
    var getResult: Result<[EntityDTO], Error> = .success([])
    var createResult: Result<EntityDTO, Error> = .success(EntityDTO(id: "1", name: "Test"))

    func getAll() async throws -> [EntityDTO] { try getResult.get() }
    func create(_ dto: EntityDTO) async throws -> EntityDTO { try createResult.get() }
}

3. Write Tests

ViewModel Tests

@Suite("FeatureViewModel Tests")
struct FeatureViewModelTests {
    // Test each action → state transition
    @Test("initial state")
    func initialState() { #expect(sut.state == .initial) }

    @Test("fetch success updates items")
    func fetchData_success() async throws { /* ... */ }

    @Test("fetch error sets error state")
    func fetchData_error() async throws { /* ... */ }
}

UseCase Tests

@Suite("FeatureUseCase Tests")
struct FeatureUseCaseTests {
    @Test("returns mapped entities from repository")
    func execute_success() async throws { /* ... */ }

    @Test("propagates repository errors")
    func execute_error() async throws { /* ... */ }
}

Mapper Tests

@Suite("FeatureMapper Tests")
struct FeatureMapperTests {
    @Test("maps DTO to Entity correctly")
    func toEntity() {
        let dto = EntityDTO(id: "1", name: "Test")
        let entity = EntityMapper.toEntity(dto)
        #expect(entity.id == "1")
        #expect(entity.name == "Test")
    }
}

Service Tests

@Suite("FeatureRequest Tests")
struct FeatureRequestTests {
    @Test("getAll has correct path and method")
    func getAll_config() {
        let request = FeatureRequest.getAll
        #expect(request.path == "entities")
        #expect(request.method == .get)
        #expect(request.body == nil)
    }
}

Coverage Requirements

• All ViewModel State enum cases reachable
• All Intent enum cases handled
• All error paths (APIError cases)
• All mapper field mappings
• Empty data edge cases
• Nil/optional handling

Test Organization

ProjectXTests/
├── Domain/
│   ├── UseCases/FeatureUseCaseTests.swift
├── Data/
│   ├── Mappers/FeatureMapperTests.swift
│   ├── Services/FeatureRequestTests.swift
├── Presentation/
│   ├── Features/FeatureViewModelTests.swift
├── Fakes/
│   ├── FakeEntityService.swift
│   ├── FakeEntityRepository.swift

Run Tests

xcodebuild test -scheme ProjectX -destination 'platform=iOS Simulator,OS=26.2,name=iPhone 17' -parallel-testing-enabled NO