Axiom axiom-testing

Use when writing ANY test, debugging flaky tests, making tests faster, or choosing Swift Testing vs XCTest. Covers unit tests, UI tests, async testing, test architecture.

install

source · Clone the upstream repo

git clone https://github.com/CharlesWiltgen/Axiom

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/CharlesWiltgen/Axiom "$T" && mkdir -p ~/.claude/skills && cp -r "$T/.claude-plugin/plugins/axiom/skills/axiom-testing" ~/.claude/skills/charleswiltgen-axiom-axiom-testing && rm -rf "$T"

manifest: .claude-plugin/plugins/axiom/skills/axiom-testing/SKILL.md

source content

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.

Quick Reference

Symptom / Task	Reference
Writing unit tests, Swift Testing (@Test, #expect)	See `skills/swift-testing.md`
Making tests run without simulator	See `skills/swift-testing.md`
Parameterized tests, tags, traits	See `skills/swift-testing.md`
Migrating from XCTest to Swift Testing	See `skills/swift-testing.md`
Testing async/await functions	See `skills/testing-async.md`
confirmation for callbacks	See `skills/testing-async.md`
@MainActor tests, parallel execution	See `skills/testing-async.md`
Writing UI tests, XCUITest	See `skills/ui-testing.md`
Condition-based waiting patterns	See `skills/ui-testing.md`
Recording UI Automation (Xcode 26)	See `skills/ui-testing.md`
Network conditioning, multi-factor testing	See `skills/ui-testing.md`
XCUIElement queries, waiting strategies	See `skills/xctest-automation.md`
Accessibility identifiers, test plans	See `skills/xctest-automation.md`
CI/CD test execution	See `skills/xctest-automation.md`
Record/Replay/Review workflow (Xcode 26)	See `skills/ui-recording.md`
Test plan multi-configuration replay	See `skills/ui-recording.md`
Enhancing recorded tests for stability	See `skills/ui-recording.md`

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"];
}

Writing unit tests / Swift Testing? →
```
skills/swift-testing.md
```
Testing async/await code? →
```
skills/testing-async.md
```
Writing UI tests / XCUITest / flaky tests? →
```
skills/ui-testing.md
```
XCUIElement queries, waiting, test plans, CI? →
```
skills/xctest-automation.md
```
Record UI interactions (Xcode 26)? →
```
skills/ui-recording.md
```
Flaky tests / race conditions (Swift Testing)? → test-failure-analyzer (Agent)
Tests crash / environment wrong? → See axiom-build (skills/xcode-debugging.md)
Run tests from CLI / parse results? → test-runner (Agent)
Fix failing tests automatically? → test-debugger (Agent)
Want test quality audit? → testing-auditor (Agent) or
```
/axiom:audit testing
```
Automate without XCUITest / AXe CLI? → simulator-tester (Agent) + See axiom-xcode-mcp (skills/axe-ref.md)

Swift Testing vs XCTest Quick Guide

Need	Use
Unit tests (logic, models)	Swift Testing
UI tests (tap, swipe, assert screens)	XCUITest (XCTest)
Tests without simulator	Swift Testing + Package/Framework
Parameterized tests	Swift Testing
Performance measurements	XCTest (XCTMetric)
Objective-C tests	XCTest

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

Thought	Reality
"Simple test question, I don't need the skill"	Proper patterns prevent test debt. `skills/swift-testing.md` has copy-paste solutions.
"I know XCTest well enough"	Swift Testing is significantly better for unit tests. Migration guide included.
"Tests are slow but it's fine"	Fast tests enable TDD. `skills/swift-testing.md` shows how to run without simulator.
"I'll fix the flaky test with a sleep()"	sleep() makes tests slower AND flakier. `skills/ui-testing.md` has condition-based waiting.
"I'll add tests later"	Tests written after implementation miss edge cases.

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)