Testing

You MUST use this skill for ANY testing-related question, including writing tests, debugging test failures, making tests faster, or choosing between testing approaches.

Bundled tools on Claude Code: if command -v <tool> finds nothing (hooks off or --bare), use <plugin-root>/tools/<tool> in place of the bare name; <plugin-root> is two levels above this skill's Base directory for this skill: path.

Can't launch Axiom agents? Where this router sends you to an agent, follow its procedure inline. Over MCP, axiom_get_agent returns it; elsewhere, read its file below, which needs only file search and read.

Available here: skills/test-failure-analyzer.md, skills/testing-auditor.md.

For any other agent, over MCP axiom_get_agent returns it too; run its xclog, xcsym and xcprof steps with the axiom_xclog_*, axiom_xcsym_* and axiom_xcprof_* tools. Elsewhere, search Axiom's skills for skills/<agent>.md; if there is none, do that work yourself with this suite's skills, using any Axiom tool on your PATH.

Quick Reference

Decision Tree

digraph testing {
    start [label="Testing task" shape=ellipse];
    what [label="What kind of test?" shape=diamond];

    start -> what;
    what -> "skills/swift-testing.md" [label="unit tests,\nSwift Testing,\nfast tests"];
    what -> "skills/testing-async.md" [label="testing async code,\ncallbacks,\nconfirmation"];
    what -> "skills/ui-testing.md" [label="UI tests,\nflaky tests,\nrecording"];
    what -> "skills/xctest-automation.md" [label="XCUITest patterns,\nelement queries"];
    what -> "skills/ui-recording.md" [label="Xcode 26\nRecord/Replay/Review"];
    what -> "axiom-ai (skills/foundation-models-evaluations.md)" [label="generative AI feature\n(nondeterministic output)"];
}

1. Writing unit tests / Swift Testing? → skills/swift-testing.md
2. Testing async/await code? → skills/testing-async.md
3. Writing UI tests / XCUITest / flaky tests? → skills/ui-testing.md
4. XCUIElement queries, waiting, test plans, CI? → skills/xctest-automation.md
5. Record UI interactions (Xcode 26)? → skills/ui-recording.md
6. Flaky tests / race conditions (Swift Testing)? → test-failure-analyzer (Agent)
7. Tests crash / environment wrong? → See axiom-build (skills/xcode-debugging.md)
8. Run tests from CLI / parse results? → test-runner (Agent)
9. Fix failing tests automatically? → test-debugger (Agent)
10. Want test quality audit? → testing-auditor (Agent) or /axiom:audit testing
11. Automate without XCUITest / AXe CLI? → simulator-tester (Agent) + See axiom-xcode-mcp (skills/axe-ref.md)
12. Testing a Foundation Models / generative feature? → See axiom-ai (skills/foundation-models-evaluations.md) for the discipline (dataset design, guardrails vs optimization target, judge calibration), then axiom-ai (skills/foundation-models-evaluations-ref.md) for the API. The Evaluations framework (OS27) runs inside Swift Testing via the .evaluates trait — it doesn't replace it. A model isn't a pure function, so you score outputs against a dataset and gate on an aggregate metric instead of asserting on one exact string.

Swift Testing vs XCTest Quick Guide

Critical Patterns

Swift Testing (skills/swift-testing.md):

• @Test/@Suite macros, #expect/#require assertions
• Parameterized testing for eliminating repetitive tests
• Fast tests architecture: Package extraction, Host Application: None
• Reliable async testing with withMainSerialExecutor and TestClock
• Migration guide from XCTest (comparison table)
• XCTestCase + Swift 6.2 MainActor compatibility fix

Async Testing (skills/testing-async.md):

• confirmation for single/multiple callbacks
• expectedCount: 0 to verify something never happens
• @MainActor test isolation
• Timeout control with .timeLimit
• Parallel execution gotchas and .serialized

UI Testing (skills/ui-testing.md):

• Condition-based waiting (replaces sleep())
• Recording UI Automation (Xcode 26)
• Network conditioning for 3G/LTE testing
• Multi-factor testing (device size + network speed)
• Crash debugging from UI test failures

XCUITest Automation (skills/xctest-automation.md):

• Element identification with accessibilityIdentifier
• Waiting strategies (appear, disappear, hittable)
• Test plans for multi-configuration testing
• CI/CD integration with parallel execution

UI Recording (skills/ui-recording.md):

• Xcode 26 Record/Replay/Review workflow
• Enhancing recorded code for stability
• Query selection guidelines
• Test plan configuration for multi-language replay

Automated Scanning

Test quality audit → Launch testing-auditor agent or /axiom:audit testing (maps test coverage shape against production code, detects flaky patterns and speed issues, identifies untested critical paths, scores overall test health)

Flaky test analysis → Launch test-failure-analyzer agent (scans for patterns causing intermittent failures in Swift Testing: missing confirmation, shared mutable state, missing @MainActor)

Anti-Rationalization

Example Invocations

User: "How do I write a unit test in Swift?" → Read: skills/swift-testing.md

User: "My UI tests are flaky in CI" → Check codebase: XCUIApplication/XCUIElement? → skills/ui-testing.md → Check codebase: @Test/#expect? → test-failure-analyzer (Agent)

User: "How do I test async code without flakiness?" → Read: skills/testing-async.md

User: "What's the Swift Testing equivalent of XCTestExpectation?" → Read: skills/testing-async.md

User: "I want my tests to run faster" → Read: skills/swift-testing.md (Strategy 1: Package extraction)

User: "Should I use Swift Testing or XCTest?" → Read: skills/swift-testing.md (Migration section) + this decision tree

User: "How do I record UI automation in Xcode 26?" → Read: skills/ui-recording.md

User: "Run my tests and show me what failed" → Invoke: test-runner (Agent)

User: "Audit my tests for quality issues" → Invoke: testing-auditor (Agent)