Borrowing it
Nothing to install: this file belongs to justifi-tech/web-component-library. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/justifi-tech/web-component-library/main/.claude/skills/testing/SKILL.mdgit clone --depth 1 https://github.com/justifi-tech/web-component-libraryWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/justifi-tech/web-component-library/testing)<a href="https://agentmods.dev/skills/justifi-tech/web-component-library/testing"><img src="https://agentmods.dev/badge/skills/justifi-tech/web-component-library/testing/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/justifi-tech/web-component-library/testing"><img src="https://agentmods.dev/badge/skills/justifi-tech/web-component-library/testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00000 | $0.04380 |
| Opus 5.5 | $0.00000 | $0.01752 |
| Sonnet 5.5 | $0.00000 | $0.00876 |
| Haiku 4.5 | $0.00000 | $0.00438 |
Grade A, and why
testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 298 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Testing
Two tiers. Use the cheaper one that can check your change. If the code is hard to test at that level, fix the code instead of moving up.
| Tier | Lives in | Runner | Observes |
|---|---|---|---|
| Spec (unit / component) | packages/webcomponents/src/** |
stencil test --spec — Jest + Stencil's mock DOM |
One concept: a util, an entity, an action factory, or one component's rendered output |
| E2E | apps/component-examples/e2e/ |
Playwright + Chromium | A real flow against the real API, driven through the Express example app |
packages/types and docs have no test script — nothing runs there.
apps/component-examples/e2e/README.md states the gate between the two: E2E covers cross-boundary interactions (API calls, navigation, iframe communication, multi-component flows). If rendering the component in isolation can verify it — rendered output, emitted events, disabled states — it is a spec test.
When you change component structure or behavior, check for tests that break, including ones you didn't write. Update outdated assertions instead of deleting them. Adding one test while leaving six existing assertions failing means the work isn't finished.
Running tests
# whole spec suite
pnpm --filter @justifi/webcomponents test
# one file, or one test name
pnpm --filter @justifi/webcomponents test -- payments-list
pnpm --filter @justifi/webcomponents test -- -t "renders properly with fetched data"
# lint (must be clean — `--max-warnings 0`)
pnpm --filter @justifi/webcomponents lint
# E2E — starts the example server itself if :3000 is free. See the E2E section.
pnpm test:e2e
# live component work: Stencil watcher + examples server. Never exits — background it.
pnpm dev:server
Every package script is allowed, build and dev:server included. format and clean have wide blast radius — announce before running either.
Three traps, each of which has bitten someone:
- Prefer the
--filterform over rootpnpm test. Rootpnpm testisturbo run test, andturbo.jsondeclarestestwithdependsOn: ["build"]. It works, it is just slower for no benefit: spec tests compile their own sources through Stencil's Jest preset and never readdist/. Reach for rootpnpm testwhen you want the build validated too. npx stencil testdoes not work here —npm error could not determine executable to run. Usepnpm --filterorpnpm exec.- Don't trust the exit code through a pipe.
cmd | tailreportstail's status, not the runner's. Read the output and look for theTests:line — its absence is the failure signal.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 298 lines · 0 tokens per session scan A 785ff7c89b33
testing is a skill published in the GitHub repository justifi-tech/web-component-library (5 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 4,380 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-24.
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