WJTTC Championship Tester
"We break things so others never have to know they were broken."
Apply F1-inspired standards to software testing. When brakes must work flawlessly at race pace, so must the code in production. This skill executes test plans and files reports β it is the driver, not the engineer. To plan and generate the suite, use wjttc-builder.
When to use this skill
- Running an existing or just-written test plan and reporting outcomes
- Reproducing and root-causing a reported bug
- Edge-case / error-handling / regression validation
- Auditing whether the suite's CI signal can still be trusted
- Producing a WJTTC report with a tier verdict
The WJTTC five tiers
Triage every test by blast radius. The first three set severity; Tyre and Pit cover durability and the release gate.
| Tier | Symbol | Meaning | Examples |
|---|---|---|---|
| Brake | π¨ | Life-critical β failure is catastrophic | data loss, auth bypass, payment errors, destructive ops without confirm |
| Engine | β‘ | Performance-critical β wrong results / poor UX | API accuracy, data transforms, calculations, format compliance, perf |
| Aero | π | Polish & edge cases β minor inconvenience | UI quirks, rare message formatting, optional-feature edges, docs |
| Tyre | π | Durability under load β degradation over time | stress/volume, concurrency, memory growth, large inputs |
| Pit | π§ | Release gate β the stop that lets you go | smoke/regression suite, CI green, the WJTTC report filed |
Test Brake first. If the brakes don't work, nothing else matters.
Step 0 β Signal Integrity pre-audit (run BEFORE adding/running anything new)
Red CI is a contract: it must always mean "stop, look, fix." A suite with high coverage but flaky reds is less trustworthy than a smaller suite with zero false alarms β because the team has stopped reading the reds. Fix the signal before you add more tests.
Method β classify the last 30 days of CI failures:
| Bucket | Definition | Verdict |
|---|---|---|
| Real bug | Red mapped to a real defect; fixed by a code change | β Signal worked |
| Flake | Timing/network/concurrency noise; passed on rerun, no code change | β Test design defect |
| Infra | Missing secret, runner image change, upstream dep β not the code | β Workflow design defect |
Signal Integrity Score: SI = Real bugs / (Real bugs + Flakes + Infra) Γ 100
| SI % | Verdict | Action |
|---|---|---|
| 100% | βͺ | Maintain β exemplary signal |
| 95β99% | β Championship | Annotate any flake immediately |
| 85β94% | β Acceptable | Schedule the flake-class fix this sprint |
| 70β84% | β Eroding | Stop adding tests β fix flakes first |
| <70% | β Dead signal | Block merges until signal restored |
Eliminate on sight: hard absolute-time perf asserts on shared runners (expect(t).toBeLessThan(30)) β move to a non-gating workflow; network calls in the main suite β mock at the boundary; concurrency tests without explicit ordering; secret-dependent steps that hard-fail when missing β grey-skip.
The inverse rule: green CI that passes while something is broken is equally a violation. If a real bug shipped despite green, write the regression test BEFORE the fix lands.
The conversation is the real gate. CI is supporting infrastructure for the human + AI audit; flaky CI wastes the audit's bandwidth. Signal Integrity keeps CI worthy of the conversation.
Execution loop
- Scope β what should it do? happy path, edges, failure modes, perf targets, tier of each.
- Audit signal (Step 0) before trusting or extending the suite.
- Run each test: set up, prepare data, execute, observe actual vs expected, record pass/fail/blocked, capture evidence on failure.
- Reproduce every failure deterministically; root-cause it; note the fix.
- Tier coverage check β confirm every test is tiered:
faf wjttc --path tests # audit tier coverage (vendor-neutral) faf wjttc --strict --json # CI gate: non-zero if any test is untiered - Report β file the WJTTC report (below), then surface the tier verdict.
WJTTC report format
Save reports to ./wjttc-reports/ in the project under test (or a path the user specifies). Never write to an absolute/personal path. Name files YYYY-MM-DD-{project}-{feature}-tests.yaml.
---
# WJTTC Test Report
project: "project-name"
feature: "feature-being-tested"
date: "2026-06-26"
tier: "Engine" # Brake | Engine | Aero | Tyre | Pit
result: "PASS" # PASS | FAIL | BLOCKED
environment: "OS, runtime version, key deps"
---
## Summary
objective: What was tested
totals: { total: 25, passed: 23, failed: 2, blocked: 0, pass_rate: "92%" }
## Failures
- name: "Long-string handling"
tier: "Engine β‘"
status: "FAIL"
steps: ["...", "..."]
expected: "Handle gracefully"
actual: "Crash"
error: "RangeError: ..."
root_cause: "Unbounded buffer"
fix: "Cap input length / stream"
## Edge cases
- { case: "Empty string", input: "''", expected: "error", actual: "error", status: "PASS" }
- { case: "Unicode", input: "ποΈ", expected: "stored", actual: "stored", status: "PASS" }
## Performance
- { op: "file read", target: "<50ms", actual: "18ms", status: "PASS" }
- { op: "parse YAML", target: "<50ms", actual: "12ms", status: "PASS" }
## Bugs found
- id: 1
title: "..."
severity: "Brake" # tier doubles as severity
reproducibility: "Always"
impact: "Who is affected, how serious"
fix: "..."
## Coverage
tested: ["happy path", "edges", "error handling", "perf"]
not_tested: ["concurrent access", "files >100MB"]
## Verdict
tier: "β Silver" # from the tier table below
to_next: ["Fix 2 failing Engine tests", "Add Tyre concurrency tests"]
Tier verdict
Map the pass rate (or SI score) to the single canonical FAF tier ladder. No second ladder, no medals.
| Score | Tier | Symbol |
|---|---|---|
| 100% | Trophy | βͺ |
| 99% | Gold | β |
| 95% | Silver | β |
| 85% | Bronze | β |
| 70% | Green | β |
| 55% | Yellow | β |
| 1% | Red | β |
| 0% | White | β‘ |
The FAF score is deterministic β same input, same score. A test report should be just as falsifiable: every verdict traces to a reproducible run. FAF doesn't lie.
WJTTC method notes
- Test with real data, not just sanitized inputs β anonymized production data, messy inputs, production-like volume.
- Document every failure so it can be reproduced: what failed, how to repro, why it matters, how to fix.
- Tier before you test β severity is the tier, so triage first;
faf wjttcenforces that nothing ships untiered. - Wire it into CI with TAF receipts so the report is part of the record, not a one-off:
faf taf setup --write # create .github/workflows/taf.yml (test receipts) faf score --json # deterministic score snapshot for the receipt
Quick checklist (before release)
- Signal Integrity audited (SI β₯ 85%)
- Brake tests pass β zero tolerance
- Edges + error handling tested
- Tyre: behaves under load / concurrency
-
faf wjttc --strictgreen β every test tiered - Regression (Pit) suite passes
- WJTTC report filed in
./wjttc-reports/ - Pass rate β₯ 85% (β Bronze, production-ready)
Resources
- Website: https://faf.one Β· Skills Site: https://skills.faf.one
- faf-cli: https://github.com/Wolfe-Jam/faf-cli
- Sibling skill: wjttc-builder (plan + generate the suite)
Made with π§‘ by wolfejam.dev β "We break things so others never have to know they were broken."
Limitations
- Use this skill only when the task clearly matches its upstream source and local project context.
- Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes.
- Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.