Swift Testing Standards

Priority: P0

Implementation Guidelines

XCTest Framework

• Standard Naming: Test functions must be prefixed by 'test' (e.g.,

  func testUserLoginSuccessful()

  ).
• Setup/Teardown: Use

  setUpWithError()

  and

  tearDownWithError()

  for environment management.
• Assertions: Use specific assertions:

  XCTAssertEqual

  ,

  XCTAssertNil

  ,

  XCTAssertTrue

  , etc.

Async Testing

• 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.

Test Organization

• 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: A test that only runs code is not a test.

References

• XCTest Patterns & Async Tests