| name | swift-testing |
| description | Write XCTest cases, async tests, and organized test suites in Swift. Use when writing XCTest cases, async tests, or organizing test suites in Swift. |
| metadata | {"triggers":{"files":["**/*Tests.swift"],"keywords":["XCTestCase","XCTestExpectation","XCTAssert"]}} |
Swift Testing Standards
Priority: P0 (CRITICAL)
Write XCTest Cases
- Standard Naming: Test functions must prefixed by 'test' (e.g.,
func testUserLoginSuccessful()).
- Setup/Teardown: Use
setUpWithError() and tearDownWithError() for environment management.
- Assertions: Use specific assertions:
XCTAssertEqual, XCTAssertNil, XCTAssertTrue, etc.
See implementation examples for XCTest setup/teardown, async tests, and UI test patterns.
Test Async Code
- Async/Await: Mark test methods as
async throws and use try await directly inside them.
- Expectations: Use
XCTestExpectation for callback-based async logic. Call expectation then fulfill() when done; then wait(for: [exp], timeout: 2.0) to block.
- Timeout: Always set reasonable timeouts for expectations to avoid hanging CI.
Organize Test Suites
- Unit Tests: Use protocols for dependencies and inject them via constructor (e.g.,
init(service: ServiceProtocol)). Focus on logic isolation using mocks/stubs.
- UI Tests: Test user flows using
XCUIApplication and accessibility identifiers.
- Coverage: Aim for high coverage on critical business logic and state transitions.
Anti-Patterns
- No Thread.sleep: Use expectations or await.
- No force unwrap in tests: Use XCTUnwrap() for better failure messages.
- No assertion-free tests: test that only runs code not test.
References
Canonical response anchors
When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:
- Inject them via constructor
- Use protocols
- prefixed by 'test'
