Swift Testing Code Review

Quick Reference

Review Checklist

• Expressions embedded directly in #expect (not pre-computed booleans)
• #require used only for preconditions, #expect for assertions
• Error tests check specific types (not generic (any Error).self)
• Parameterized tests with pairs use zip() (not Cartesian product)
• No logic mirroring implementation in parameterized expected values
• Async sequences tested with confirmation(expectedCount:)
• Completion handlers use withCheckedContinuation, not confirmation
• .serialized applied only where necessary (shared resources)
• Sibling serialized suites nested under parent if mutually exclusive
• No assumption of state persistence between @Test functions
• Disabled tests have explanations and bug links

When to Load References

• Reviewing #expect or #require usage -> expect-macro.md
• Reviewing @Test with arguments or traits -> parameterized.md
• Reviewing confirmation or async testing -> async-testing.md
• Reviewing @Suite or test organization -> organization.md

Review Questions

1. Could pre-computed booleans in #expect lose diagnostic context?
2. Is #require stopping tests prematurely instead of revealing all failures?
3. Are multi-argument parameterized tests creating accidental Cartesian products?
4. Could zip() silently drop test cases due to unequal array lengths?
5. Are completion handlers incorrectly tested with confirmation?