ax-testing

Testing

Quick Patterns

Swift Testing Basics

import Testing

@Test("User has correct name") func userName() {
    let user = User(name: "Alice")
    #expect(user.name == "Alice")
}

@Test func fetchUser() async throws {
    let user = try await api.fetch(id: 1)
    #expect(user.isActive)
}

// Unwrap or fail fast
let first = try #require(items.first)
#expect(first.isValid)

// Error testing
#expect(throws: ValidationError.invalidEmail) {
    try validate(email: "bad")
}

Suites and Traits

@Suite("Video Tests")
struct VideoTests {
    let video = Video(named: "sample.mp4") // Fresh per test

    @Test func duration() { #expect(video.duration == 120) }

    @Test(.disabled("Backend not ready")) func upload() async { }
    @Test(.timeLimit(.minutes(1))) func transcode() async { }
    @Test(.bug("https://github.com/org/repo/issues/42")) func edgeCase() { }
}

extension Tag {
    @Tag static var networking: Self
    @Tag static var slow: Self
}

@Test(.tags(.networking, .slow)) func integrationTest() async { }

Parameterized Tests

@Test(arguments: [IceCream.vanilla, .chocolate, .strawberry])
func flavorWithoutNuts(_ flavor: IceCream) {
    #expect(!flavor.containsNuts)
}

// Two collections = all combinations (cartesian product)
@Test(arguments: [1, 2, 3], ["a", "b", "c"])
func allCombinations(number: Int, letter: String) { }

// Paired values only
@Test(arguments: zip([1, 2, 3], ["one", "two", "three"]))
func paired(number: Int, name: String) { }

Async Testing

// Callback -> confirmation (replaces XCTestExpectation)
@Test func notificationFires() async {
    await confirmation { confirm in
        NotificationCenter.default.addObserver(forName: .didUpdate, object: nil, queue: .main) { _ in
            confirm()
        }
        triggerUpdate()
    }
}

// Multiple events
await confirmation("eaten", expectedCount: 10) { confirm in
    jar.onEaten = { confirm() }
    await jar.eatAll()
}

// Verify never happens
await confirmation(expectedCount: 0) { confirm in
    cache.onEviction = { confirm() }
    cache.store("small")
}

// MainActor isolation
@Test @MainActor func viewModelUpdates() async {
    let vm = ViewModel()
    await vm.load()
    #expect(vm.items.count > 0)
}