swift-testing-expert

$29

• Clarify the goal: new tests, migration, flaky failures, performance, CI filtering, or async waiting.

• Collect minimal facts:

• Xcode/Swift version and platform targets

• Whether tests currently use XCTest, Swift Testing, or both

• Whether failures are deterministic or flaky

• Whether tests access shared resources (database, files, network, global state)

• Branch quickly:

• repetitive tests -> parameterized tests

• noisy or flaky failures -> known issue handling and test isolation

• migration questions -> XCTest mapping and coexistence strategy

• async callback complexity -> continuation/await patterns

Routing map (read the right reference fast)

• Test building blocks and suite organization -> references/fundamentals.md

• #expect, #require, and throw expectations -> references/expectations.md

• Traits, tags, and Xcode test-plan filtering -> references/traits-and-tags.md

• Parameterized test design and combinatorics -> references/parameterized-testing.md

• Default parallel execution, .serialized, isolation strategy -> references/parallelization-and-isolation.md

• Test speed, determinism, and flakiness prevention -> references/performance-and-best-practices.md

• Async waiting and callback bridging -> references/async-testing-and-waiting.md

• XCTest coexistence and migration workflow -> references/migration-from-xctest.md

• Test navigator/report workflows and diagnostics -> references/xcode-workflows.md

• Index and quick navigation -> references/_index.md

Common pitfalls -> next best move

• Repetitive testFooCaseA/testFooCaseB/... methods -> replace with one parameterized @Test(arguments:).

• Failing optional preconditions hidden in later assertions -> try #require(...) then assert on unwrapped value.

• Flaky integration tests on shared database -> isolate dependencies or in-memory repositories; use .serialized only as a transition step.

• Disabled tests that silently rot -> prefer withKnownIssue for temporary known failures to preserve signal.

• Unclear failure values for complex types -> conform type to CustomTestStringConvertible for focused test diagnostics.

• Test-plan include/exclude by names -> use tags and tag-based filters instead.

Verification checklist

• Confirm each test has a single clear behavior and expressive display name when needed.

• Confirm prerequisites use #require where failure should stop the test.

• Confirm repeated logic is parameterized instead of duplicated.

• Confirm tests are parallel-safe or intentionally serialized with rationale.

• Confirm async code is awaited and callback APIs are bridged safely.

• Confirm migration keeps unsupported XCTest-only scenarios on XCTest.

References

• references/_index.md

• references/fundamentals.md

• references/expectations.md

• references/traits-and-tags.md

• references/parameterized-testing.md

• references/parallelization-and-isolation.md

• references/performance-and-best-practices.md

• references/async-testing-and-waiting.md

• references/migration-from-xctest.md

• references/xcode-workflows.md