writing-swift-unit-tests

What problem does it solve?

Reduces flakiness, implementation coupling, and inconsistent practices when adding or modifying Swift unit tests by providing clear conventions and a checklist to produce deterministic, maintainable tests.

Core Features & Use Cases

• Framework guidance: Prefer Swift Testing for new tests and use XCTest only when extending existing XCTest-based files, with a documented rationale when deviating.
• Conventions for clarity: Require literal test names, avoid redundant suite annotations, and use assertion helpers (#expect / #require) rather than XCTAssert in Swift Testing.
• Quality and determinism: Emphasize observable behavior testing, minimal mocking, single behavioral intent per test, async and cancellation verification, and avoidance of time-based sleeps.
• Use case: When adding tests for a networking or business logic component, follow these rules to ensure tests are deterministic, focused on behavior, and easy to maintain.

Quick Start

Create or update the unit test file using Swift Testing by default, name tests with descriptive literal names, use #expect and #require for assertions, and verify deterministic behavior including edge and failure cases.