Test Analysis Extensions

Swift Test Frameworks Reference (XCTest, Swift Testing)

Reference data for analyzing Swift test code. Used by the polyglot test analysis skills.

Capability tags

Test File Identification

Both frameworks can coexist in one target.

Assertion APIs

Sleep/Delay Patterns

XCTestExpectation + wait(for:timeout:) is the idiomatic async-coordination pattern in XCTest — not a sleep smell.

Skip/Ignore Annotations

Exception Handling — Idiomatic Alternatives

// XCTest:
XCTAssertThrowsError(try service.placeOrder(emptyOrder)) { error in
    guard case OrderError.empty = error else {
        XCTFail("Expected .empty, got \(error)")
        return
    }
}

// Swift Testing:
#expect(throws: OrderError.self) {
    try service.placeOrder(emptyOrder)
}

// Specific case (Swift Testing):
let err = try #require(throws: OrderError.self) { try service.placeOrder(emptyOrder) }
#expect(err == .empty)

Flag manual do { try fn(); XCTFail("expected throw") } catch { ... } patterns and recommend the framework-native form.

Mystery Guest — Common Swift Patterns

Integration Test Markers

• Folder convention: IntegrationTests/, UITests/, E2ETests/

• Class name suffix: *IntegrationTests, *UITests

• XCUITest (XCUIApplication, XCUIElement) → UI/E2E test

• Swift Testing @Tag named .integration or .ui

Setup/Teardown

Swift Testing creates a fresh instance per test by default — fields initialized in init are reset between tests.

Tag/Trait Attributes (for test-tagging)

For Swift Testing, define tags in a single module-level location:

extension Tag {
    @Tag static var positive: Self
    @Tag static var negative: Self
    @Tag static var boundary: Self
    @Tag static var integration: Self
}

Language-specific calibration notes

• Swift Testing #expect continues on failure; try #require aborts. Tests that mix preconditions and assertions should use try #require for preconditions.

• XCTAssert* continues on failure — tests with multiple cascading assertions may log many failures from one root cause.

• Async tests must await — missing await causes warnings and silent skips on async APIs.

• Combine tests with expectation(description:) are XCTest's idiomatic async pattern; not a sleep smell.

• Snapshot testing (SnapshotTesting library) — treat snapshot comparisons as legitimate assertions; flag stale records.

• Parametrized tests (@Test(arguments: [...])) are NOT duplicates.

• Test plans (.xctestplan) can filter by tags / configurations; mention as a structural alternative to per-test tagging.

• continueAfterFailure — when false, XCTest stops on first failure (useful for fast-fail integration tests).