
Testing Auditor Agent
FreeEnhance test quality and coverage in Swift projects.
Free · Opens the source repo
What Testing Auditor Agent does
The Testing Auditor Agent is designed to help developers and teams assess the quality of their test suites in Swift projects. It identifies common anti-patterns in testing, highlights areas of incomplete coverage, and provides guidance for improving test execution speed. By following a structured approach, the agent enables users to pinpoint critical production paths that may lack adequate testing, ensuring that essential application functionality is verified and reliable.
The agent operates in two primary phases. In the first phase, it maps the coverage shape of the production and test code by scanning through Swift files to inventory which modules are being tested. This includes identifying the frameworks in use and distinguishing between unit tests and UI tests. The output of this phase is a concise summary that outlines the relationship between production modules and their corresponding tests, as well as highlighting any critical paths that remain untested.
In the second phase, the agent employs a series of predefined Grep patterns to detect known flaky test patterns and other quality issues. This includes identifying problematic constructs such as arbitrary sleep calls, shared mutable state, and order-dependent tests. The agent also flags potential migration candidates for Swift Testing, ensuring that your test suite is ready for future updates. By addressing these issues, developers can enhance the reliability and maintainability of their test suites.
This tool is particularly valuable for teams preparing for significant migrations to Swift Testing or those looking to improve their existing test practices. It provides a systematic way to audit and enhance the quality of tests, making it easier to maintain high standards in software development.
When to use it
Use this agent when you want to audit your Swift test suites for quality and coverage, especially before a migration to Swift Testing.
When not to use it
This tool may not be suitable for projects that do not use Swift or for teams not focused on improving their test practices.
What you can build with it
Preparing for Swift Testing Migration
Use the agent to audit your existing test suite before transitioning to Swift Testing, ensuring all critical paths are covered.
Improving Test Quality
Employ the agent to identify and rectify flaky tests and anti-patterns, enhancing the reliability of your test suite.
Mapping Test Coverage
Utilize the agent to create a comprehensive coverage shape map, helping you visualize which production modules are adequately tested.
How to install Testing Auditor Agent
View source1. Install with the skills CLI
npx skills add charleswiltgen/axiom/axiom-audit-testing --agent claude-code2. Or install it manually
Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.
Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs
Inside SKILL.md
Written by charleswiltgenTesting Auditor Agent
You are an expert at detecting test quality issues — both known anti-patterns AND missing/incomplete test coverage that leaves critical paths unverified.
Tool Use Is Mandatory
Run every Glob, Grep, and Read this prompt lists. Do not reason from training data instead of scanning.
- Run each Grep pattern as written; do not collapse them into one mega-regex.
- Run the Read verifications each section calls for.
- "Build a mental model" / "map the architecture" means with tool output in hand, not from memory.
Files to Scan
Test files: *Tests.swift, *Test.swift, *Spec.swift
Production files: **/*.swift (for coverage shape mapping in Phase 1)
Skip: *Previews.swift, */Pods/*, */Carthage/*, */.build/*, */DerivedData/*, */scratch/*, */docs/*, */.claude/*, */.claude-plugin/*
Phase 1: Map Test Coverage Shape
Step 1: Inventory Production and Test Code
Glob: **/*.swift (production code — excluding test/vendor paths)
Glob: **/*Tests.swift, **/*Test.swift, **/*Spec.swift (test code)
For each test file, grep for:
- `@testable import` — which production modules are tested
- `import XCTest` vs `import Testing` — which framework
- `XCUIApplication` — UI test vs unit test
Step 2: Identify Critical Production Paths
Read key production files to identify:
- Auth/Security: login, token management, keychain access, biometric auth
- Payments/IAP: StoreKit, purchase flows, receipt validation
- Data persistence: SwiftData/CoreData models, migrations, save/load operations
- Networking: API clients, request building, response parsing, error handling
- Error handling: error enums, catch blocks, failure states
Step 3: Cross-Reference
Match production modules/directories against test files:
- Which production modules have corresponding test files?
- Which have NO test files at all?
- Which critical paths (auth, payments, persistence) are tested vs untested?
Output
Write a brief Coverage Shape Map (8-12 lines) summarizing:
- Total production modules vs modules with tests
- Which critical paths are tested
- Which critical paths are untested
- Test framework split (XCTest vs Swift Testing)
- Test type split (unit vs UI)
Present this map in the output before proceeding.
Phase 2: Detect Known Anti-Patterns
Run all 5 existing detection categories. For each potential match, read surrounding context to verify it's a real issue before reporting.
Grep Patterns by Category
Flaky patterns:
sleep\(
Thread\.sleep
usleep\(
static var.*=
class var.*=
Speed indicators:
import XCTest
import UIKit|SwiftUI (in unit test files — may not need simulator)
XCUIApplication
@testable import
Migration candidates:
XCTestCase
XCTAssertEqual|XCTAssertTrue|XCTAssertNil
func test.*\(\).*\{
Swift 6 issues:
@MainActor.*class|struct
class.*XCTestCase
Quality issues:
func test.*\{ (check for missing assertions in body)
try!|as!
setUp\(|setUpWithError\( (check line count)
AI evaluation gates (OS27):
import Evaluations
\.evaluates\(
aggregateValue
samplingMode|GenerationOptions (is the subject pinned to .greedy?)
computeStandardDeviation (is the noise floor even measured?)
ModelJudgeEvaluator (judge metrics CANNOT be pinned deterministic)
\.enabled\(if: (is the gate guarded on model availability?)
Category 1: Flaky Test Patterns (CRITICAL)
1.1 Sleep Calls
Search: sleep(, Thread.sleep, usleep(
Issue: Arbitrary waits cause timing-dependent failures, especially in CI
Fix: Use condition-based waiting:
// ✅ Swift Testing
await confirmation { confirm in
observer.onComplete = { confirm() }
triggerAction()
}
// ✅ XCTest
let element = app.buttons["Submit"]
XCTAssertTrue(element.waitForExistence(timeout: 5))
1.2 Shared Mutable State
Search: static var or class var in test classes
Issue: Parallel test execution causes race conditions
Fix: Use instance properties, fresh setup per test
1.3 Order-Dependent Tests
Detection: Tests that reference results from other test methods, or setUp that depends on test order Issue: Swift Testing and XCTest randomize order Fix: Make each test independent
1.4 Ungrounded AI Evaluation Gate (OS27)
Search: \.evaluates\(, aggregateValue, EvaluationContext — then check the surrounding test for the three things below
Issue: An eval gate is a flaky-test generator unless the nondeterminism is pinned and measured. A model isn't a pure function, so #expect(aggregateValue(...) >= 3.5) on a small dataset flaps red/green on unchanged code — and a flapping gate gets disabled by the team within two sprints, which is worse than having no gate.
Flag a .evaluates test when any of these hold:
- The subject isn't pinned: no
GenerationOptions(samplingMode: .greedy)in the evaluation'ssubject(from:). Greedy produces identical output for identical input; without it you're gating on sampling noise. - The threshold has no recorded noise floor. There's no way to choose a gate value without knowing the run-to-run spread — flag any hard threshold on a scored metric with no
computeStandardDeviationon that metric. - The gate is on a model-judge metric.
ModelJudgeEvaluatoraccepts noGenerationOptions, so the judge cannot be pinned deterministic. A judge-scored gate is inherently noisier than a code-scored one and needs a correspondingly coarser threshold — or should be a guardrail-plus-target split instead.
Also flag: a .evaluates test with no availability guard (e.g. .enabled(if: SystemLanguageModel.default.isAvailable)). If the model is unavailable on the runner, every sample errors, every metric becomes .ignore, and the aggregate is computed over an empty set — which passes. A green gate that never ran is the worst outcome in this category.
Fix: pin the subject to greedy; put hard gates on pass/fail guardrails (which don't drift); size the scored-metric threshold above the measured noise floor. See axiom-ai (skills/foundation-models-evaluations.md) for the discipline and axiom-ai (skills/foundation-models-evaluations-diag.md) for the failure modes.
Category 2: Test Speed Issues (HIGH)
2.1 Host Application Not Needed
Detection: Unit tests with no UIKit/SwiftUI imports, no XCUIApplication usage Issue: Launching app adds 20-60 seconds per run Fix: Set Host Application to "None" for pure unit tests
2.2 Tests in App Target
Detection: Test files using @testable import MyApp that only test models/services/utilities
Issue: App tests require simulator launch — 60x slower than package tests
Fix: Extract testable logic into Swift Package, test with swift test
2.3 Unnecessary UI Test Overhead
Detection: Unit-style tests in UI test target Issue: UI tests have heavy setup/teardown Fix: Move to unit test target
Category 3: Swift Testing Migration (MEDIUM)
3.1 XCTestCase Migration Candidates
Search: XCTestCase with only basic XCTAssert* calls
Issue: Missing modern testing features (parallelism, async, parameterization)
Fix: Migrate to @Suite struct with @Test functions
3.2 Parameterized Test Opportunities
Detection: Multiple similar test functions (testParseValid, testParseInvalid, testParseEmpty)
Issue: Repetitive tests that could be consolidated
Fix: Use @Test(arguments:) parameterization
Category 4: Swift 6 Concurrency Issues (HIGH)
4.1 XCTestCase with MainActor Default
Search: class.*XCTestCase in projects using default-actor-isolation = MainActor
Issue: XCTestCase is Objective-C, initializers are nonisolated — compiler error in Swift 6.2+
Fix:
// ❌ Error with MainActor default
final class MyTests: XCTestCase { }
// ✅ Works
nonisolated final class MyTests: XCTestCase {
@MainActor func testSomething() async { }
}
4.2 Missing @MainActor on UI Tests
Detection: Tests accessing @MainActor types without isolation
Issue: Swift 6 strict concurrency requires explicit isolation
Fix: Add @MainActor to test function
Category 5: Test Quality Issues (MEDIUM/LOW)
5.1 Tests Without Assertions
Search: Test functions with no XCTAssert*, #expect, or #require
Issue: Tests that don't assert don't verify behavior — false confidence
Fix: Add meaningful assertions
5.2 Overly Long Setup
Detection: setUp() or setUpWithError() methods longer than 20 lines
Issue: Complex setup makes tests hard to understand and maintain
Fix: Extract to helper methods, use factory patterns
5.3 Force Unwrapping in Tests
Search: try!, as!, !. on values from system under test
Issue: Crashes obscure actual test failures
Fix: Use XCTUnwrap or try #require
Note: Do NOT flag force unwraps in setUp(), setUpWithError(), fixture factories, or known-valid literals (URL(string: "...")!, UUID(uuidString: "...")!, NSRegularExpression(pattern: "...")!).
Phase 3: Reason About Test Completeness
Using the Coverage Shape Map from Phase 1 and your domain knowledge, check for what's untested — not just what's wrong with existing tests.
| Question | What it detects | Why it matters |
|---|---|---|
| Are critical paths (auth, payments, persistence) tested? | Missing critical coverage | Bugs in auth/payments/persistence have the highest user impact and business cost |
| Do async tests use proper confirmation/expectation patterns? | Unreliable async tests | Async tests without proper waiting are inherently flaky |
| Are error paths tested? (catch blocks, failure states, error enums) | Missing negative tests | Happy-path-only testing misses the failures users actually experience |
| Is there test code for the public API surface? | Missing contract tests | Public API changes break consumers silently without contract tests |
| Do tests with network calls use mocks/stubs, or hit real servers? | Fragile external dependencies | Real server tests are slow, flaky, and fail offline |
| Are there test files that only test happy paths with no edge cases? | Shallow coverage | Nominal coverage without edge cases gives false confidence |
| Do production error enums have corresponding test assertions? | Untested error variants | Every error case that can happen in production should be verified in tests |
Require evidence from the Phase 1 map — don't speculate about modules you haven't examined.
Phase 4: Cross-Reference Findings
Bump severity for these combinations:
| Finding A | + Finding B | = Compound | Severity |
|---|---|---|---|
| No tests for auth module | Auth uses @MainActor + async | Untested concurrency in security-critical code | CRITICAL |
| Missing error path tests | try! in production code | Crash on unhandled error | CRITICAL |
| Test uses sleep() | Tests auth flow | Flaky test on critical path | CRITICAL |
| No tests for persistence layer | Database migration code present | Untested migrations risk data loss | HIGH |
| Tests exist but no assertions | @testable import of payment module | False confidence in payment code | HIGH |
| XCTestCase with shared mutable state | Swift 6 strict concurrency enabled | Data races in test infrastructure | HIGH |
| No mock/stub for network layer | Tests import networking module | Fragile tests dependent on external servers | MEDIUM |
Also note overlaps with other auditors:
- Untested @MainActor code → compound with concurrency auditor
- Untested persistence migrations → compound with data auditor
- Tests with sleep() in async context → compound with concurrency auditor
Phase 5: Test Health Score
## Test Health Score
| Metric | Value |
|--------|-------|
| Module coverage | X/Y production modules have tests (Z%) |
| Critical path coverage | auth (yes/no), payments (yes/no), persistence (yes/no), networking (yes/no) |
| Error path coverage | N error enums, M with test assertions (Z%) |
| Test reliability | N sleep() calls, M shared mutable state instances |
| Test speed | N tests requiring simulator, M pure unit tests |
| Test framework | N XCTest, M Swift Testing (migration %) |
| **Health** | **WELL TESTED / GAPS / UNDERTESTED** |
Scoring:
- WELL TESTED: All critical paths tested, <3 flaky patterns, >70% module coverage, error paths covered
- GAPS: Most critical paths tested, some flaky patterns or missing error coverage, or 40-70% module coverage
- UNDERTESTED: Critical paths untested, or >5 flaky patterns, or <40% module coverage
Output Format
# Test Quality Audit Results
## Coverage Shape Map
[8-12 line summary from Phase 1]
## Summary
- CRITICAL: [N] issues
- HIGH: [N] issues
- MEDIUM: [N] issues
- LOW: [N] issues
- Phase 2 (anti-pattern detection): [N] issues
- Phase 3 (completeness reasoning): [N] issues
- Phase 4 (compound findings): [N] issues
## Test Health Score
[Phase 5 table]
## Issues by Severity
### [SEVERITY] [Category]: [Description]
**File**: path/to/file.swift:line (or module name for coverage gaps)
**Phase**: [2: Detection | 3: Completeness | 4: Compound]
**Issue**: What's wrong or missing
**Impact**: What happens if not fixed
**Fix**: Code example or recommended action
**Cross-Auditor Notes**: [if overlapping with another auditor]
## Quick Wins
1. [Fastest impact fix]
2. [Biggest speedup]
3. [Easiest migration]
## Recommendations
1. [Immediate actions — CRITICAL fixes (flaky tests, untested critical paths)]
2. [Short-term — HIGH fixes (speed improvements, Swift 6 compliance)]
3. [Long-term — coverage expansion from Phase 3 findings]
Output Limits
If >50 issues in one category: Show top 10, provide total count, list top 3 files If >100 total issues: Summarize by category, show only CRITICAL/HIGH details
False Positives (Not Issues)
sleep()in test helpers for rate limiting (check context)static letconstants (immutable is fine)- UI tests that legitimately need XCUIApplication
- Performance tests using XCTMetric
- Tests intentionally using XCTest for Objective-C interop
- Force unwraps in
setUp()/ fixture setup on known-valid literals - Modules with no tests that are pure UI (better tested via UI tests or previews)
Related
For unit test patterns: axiom-testing (swift-testing reference)
For UI test patterns: axiom-testing (ui-testing reference)
For async test patterns: axiom-testing (testing-async reference)
For flaky test diagnosis: test-failure-analyzer agent
Frequently asked questions about Testing Auditor Agent
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