Ln 23 Test Suite Auditor Skill for Claude

Test Suite Auditor

Goal: Audit the test portfolio as a read-only confidence system. Determine which important failures the suite can detect, which tests cannot be trusted, and where maintenance cost exceeds unique regression value.

Execution contract: Treat the ordered checkbox workflow below as this skill's Definition of Done. Work through every item in order, and mark it complete only when its action and required evidence are complete. N/A, skipped, unavailable, or delegated items remain incomplete.

Before returning, apply this skill's verdict, decision, and approval rules to every incomplete item and prepend Checklist: X/Y complete<br>Incomplete: None | section/item — reason; outcome impact; exact next action; list every incomplete item.

Tool Routing

| Need | Preferred tool | Use it when | Fallback |

|---|---|---|---|

| Source and test inventory | Native file listing, search, manifests, and test configuration | Mapping domains, test types, runners, fixtures, and generated areas | Repository tree plus known test entrypoints |

| Test-to-code relationships | Language server or host-native code intelligence | Mapping units, callers, implementations, routes, and test targets | Naming and path search verified by direct reads |

| Execution and trust | Repository-defined test commands through the shell | Establishing pass/fail state, timing, order dependence, or reproducibility | Inspect CI results and configuration; mark execution unavailable |

| Coverage and missed behavior | Existing coverage tools and reports | Coverage data is configured and comparable to source scope | Static behavior-to-test mapping; never invent percentages |

| Flake and isolation evidence | Repeated, shuffled, parallel, or seed-controlled runs supported by the repository | A test is suspected of order, time, randomness, or shared-state dependence | History, CI logs, and code-path evidence |

| Assertion strength | Test reads, failure output, and configured mutation testing | Determining whether tests fail for meaningful behavioral defects | Counterfactual reasoning tied to specific assertions |

| Framework semantics | Official test-runner or framework documentation | A finding depends on lifecycle, fixtures, retries, isolation, or mocking behavior | Primary-source web research; otherwise mark UNVERIFIED |

Run only safe test and diagnostic commands. Do not rewrite snapshots, update golden files, regenerate fixtures, or accept changed output during the audit.

Evidence Rules

• Coverage indicates execution, not proof. Require an assertion or observable oracle for important behavior.
• A slow test is not low-value when it uniquely protects a critical journey; a fast test is not high-value when it proves framework behavior.
• A flaky failure must be separated from an intermittently failing product dependency or genuinely nondeterministic requirement.
• Deletion recommendations require proof that another test covers the same behavior and failure modes with equal or better trust.
• Merge recommendations require demonstrated duplicate or fragmented coverage and must preserve distinct business and failure scenarios, oracle strength, and failure localization; a larger test is not inherently better.
• Known regression guards and the only proof of a rare critical edge case are not deletion candidates merely because a numeric value heuristic is low.
• A real dependency is not inherently a test defect. Judge whether its version, state, ownership, reset, availability, and failure evidence make the result reproducible.
• External testing guidance becomes actionable only when it explains a concrete weakness in this suite.

Checklist

1. Map the Portfolio and Baseline

• [ ] Detect test runners, configurations, commands, directories, fixtures, factories, snapshots, golden files, manual scripts, coverage, and mutation tooling.
• [ ] Map source domains and critical entrypoints to unit, integration, contract, end-to-end, and manual test surfaces.
• [ ] Read repository instructions and CI configuration to identify required suites, environment assumptions, retries, sharding, and exclusions.
• [ ] Run the smallest representative suites, then required test gates where feasible; record environment, duration, exit status, failures, skips, and retries.
• [ ] Separate generated, vendored, example, migration-history, and infrastructure fixtures from product tests before evaluating the portfolio.
• [ ] Keep the audit read-only and disclose any caches or test artifacts created by permitted commands.

2. Audit Product Value and Coverage

• [ ] Identify uniquely critical local logic: money, authentication, authorization, data integrity, algorithms, domain rules, destructive operations, and irreversible workflows.
• [ ] Trace each critical behavior to at least one test whose oracle would fail for the corresponding defect; name/path matches and line coverage are only discovery evidence.
• [ ] Identify tests that merely re-prove language, framework, database engine, ORM, HTTP client, cryptography, serializer, or library behavior without asserting repository-owned configuration, queries, schemas, adaptation, validation, failure handling, or observable outcomes.
• [ ] Check whether end-to-end tests cross the production-shaped boundaries relevant to the risk and prove the terminal durable or user-visible outcome, not only an intermediate status, page, or mock call.
• [ ] Find critical journeys with no end-to-end proof and expensive end-to-end tests whose behavior is already covered more reliably at a lower level.
• [ ] Inspect error, retry, timeout, authorization, concurrency, migration, compatibility, and recovery behavior where those failures are plausible and costly.
• [ ] Use coverage data to locate unexecuted critical paths, then inspect behavior and assertions before reporting a gap.
• [ ] Classify portfolio actions as KEEP, ADD, UPDATE, DELETE, or MERGE, justified by impact, defect probability, uniqueness, trust, and maintenance cost; use UPDATE when valuable behavior remains but its setup, boundary, assertion, or oracle must change.

3. Audit Isolation and Determinism

• [ ] Check shared database, filesystem, environment, process, network, cache, clock, random generator, and global state for leakage between tests.
• [ ] Check setup and teardown on success and failure, unique test data, transaction boundaries, cleanup, and parallel-safe resource ownership.
• [ ] Diagnose suspected flakes with the smallest discriminating matrix available: run alone, in-suite, repeated with a fixed seed, shuffled/reversed, and parallel; preserve the first failing order, seed, worker, and environment.
• [ ] Detect time, timezone, locale, randomness, sleep, scheduler, and race sensitivity; require controllable clocks or seeds where behavior depends on them.
• [ ] For real dependencies and emulators, verify version pinning, readiness, namespace/state reset, failure cleanup, credentials, and CI availability instead of assuming either real or mocked is preferable.
• [ ] Review retries and quarantine rules so they preserve the first failure and reproducibility data rather than converting an initial failure into a silent pass.
• [ ] Distinguish test flakiness from real intermittent product defects using repeated evidence, logs, and the failing path.

4. Audit Structure, Maintenance, and Oracles

• [ ] Check whether test layout follows source domains or a clear type-based convention and whether contributors can locate the owning tests.
• [ ] Find orphan tests, disabled suites, duplicate fixtures, fragmented scenario coverage, oversized files, and flat directories that obscure ownership.
• [ ] Check test names and arrangement for behavioral intent, prerequisites, action, and expected outcome rather than implementation narration.
• [ ] Inspect assertions for specificity, negative proof, state and interaction balance, useful failure messages, and resistance to false positives.
• [ ] Flag assertion-free tests, weak truthiness checks, snapshot-only proof, broad exception acceptance, and mocks that bypass the behavior under test.
• [ ] Check that expected values come from an independent contract, example, invariant, or golden artifact rather than reproducing the implementation's calculation inside the test.
• [ ] Check mocks, fakes, emulators, and generated clients for contract drift; require a contract test or another credible comparison with the real boundary where drift could create false confidence.
• [ ] Exercise non-default configuration values where a passing test with defaults could conceal hard-coded ports, limits, timeouts, paths, or feature behavior.
• [ ] Use existing mutation results or a safe targeted counterfactual for critical weak-oracle candidates; do not mandate repository-wide mutation testing.
• [ ] Review manual tests for reproducible setup, fail-fast behavior, explicit expected evidence, idempotency, cleanup, portability, and operator documentation.
• [ ] Check fixture and helper abstraction for readability and honest defaults; hidden behavior in builders must not make important test conditions invisible.

5. Validate Findings and Report

• [ ] Research runner or framework semantics only when lifecycle, fixture, isolation, retry, or mocking behavior can change a finding; use official version-matched sources.
• [ ] Reproduce high-severity trust failures where safe, preserving command, seed, order, and environment evidence.
• [ ] Deduplicate findings that share one root cause, such as a global fixture causing multiple flaky suites.
• [ ] Classify findings as P0-P3 based on critical behavior left unproven, false confidence, delivery blockage, and maintenance drag.
• [ ] Include affected behavior, test location, evidence, missed defect class, portfolio action, and smallest credible remediation.
• [ ] Use BLOCKED when a required critical suite, environment, or oracle cannot be accessed and no credible static or historical fallback exists; use FAIL when evidence shows critical behavior is unproven, a required gate fails, or false confidence remains in an untrustworthy critical surface; use CONCERNS only for non-blocking portfolio or maintenance risk, and PASS only when required evidence is trustworthy and no critical gap remains.
• [ ] Return the verdict with trusted coverage, critical gaps, untrustworthy surfaces, portfolio actions, limitations, and residual test risk.

Output Contract

# Test Suite Audit

**Verdict:** PASS | CONCERNS | FAIL | BLOCKED

## Portfolio map and baseline
- Runners, suites, and test types
- Commands and environments executed
- Coverage, flake, and mutation evidence available

## Confidence summary
| Area | Status | Evidence |
|---|---|---|
| Critical behavior coverage | PASS / CONCERNS / FAIL | ... |
| Isolation and determinism | PASS / CONCERNS / FAIL | ... |
| Structure and maintenance | PASS / CONCERNS / FAIL | ... |
| Assertion and oracle strength | PASS / CONCERNS / FAIL | ... |

## Findings and portfolio actions
### [P0 | P1 | P2 | P3] Finding title
- Behavior and test location
- Evidence and missed defect class
- Action: KEEP / ADD / UPDATE / DELETE / MERGE
- Required change

## Residual risks
Unexecuted suites, unavailable environments, and behavior that remains unproven.