Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/udecode/plate-playground-template/testinggit clone --depth 1 https://github.com/udecode/plate-playground-templateWhat 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 | $0.00315 | $0.00315 |
| Opus 5 | $0.00158 | $0.00158 |
| Sonnet 5 | $0.00063 | $0.00063 |
| Haiku 4.5 | $0.00032 | $0.00032 |
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 yesterday.
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.
Copies of this mod
1 near-identical copy found in the catalogue:
- testing — 100% identical, 0 lines differ
What it actually says
Testing Goal
Keep tests in three buckets only:
- Pure unit tests for deterministic logic.
- Thin component or hook contract tests for real app behavior.
- Golden input or output tests when serialized output is the contract.
Hard constraints:
- Prefer Bun for the fast local loop.
- Keep the default suite fast.
- No browser or e2e coverage unless the app behavior truly needs it.
- Coverage is a hotspot tool, not a vanity score.
Core Rules
- Assert public behavior, not implementation detail.
- Keep tests next to the code they cover with
*.spec.ts[x]. - Keep helpers local. Do not import one spec from another.
- Prefer explicit assertions over snapshots.
- Delete skipped, commented, or placeholder tests instead of babysitting them.
Seam Selection
- Use plain function tests for pure logic.
- Use rendered React tests for hooks, components, rerender behavior, and DOM behavior.
- Use browser checks only when the contract is actually browser-specific.
Fixtures And Assertions
- Keep fixtures small.
- Use plain objects for simple state.
- Use
it.eachfor small behavior matrices. - In Bun + Testing Library, prefer render-returned queries over
screen. - Use direct style-property assertions instead of
toHaveStyle. - Use snapshots only when serialized output is the contract and inline assertions would be worse.
Quick Reference
- Keep tests fast and local.
- Start with the smallest seam that proves the behavior.
- Prefer explicit assertions.
- Browser checks are for real UI behavior, not lazy coverage.
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.
- yesterday First seen · 45 lines · 315 tokens per session scan A 3d47bb757fc6
testing is a cursor rule published in the GitHub repository udecode/plate-playground-template (240 stars, last pushed 11d ago), licensed MIT. It adds 315 tokens to every session, about $0.0016 per session on Opus 5. 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 2026-08-30.
Other cursor rules, from other repositories
components
React component architecture for creating composable, accessible components with data attributes. Use when creating/updating composable components, not for higher-level feature/page components.
react
React patterns with destructured props, compiler optimization, Effects, and Tailwind v4 syntax. ALWAYS use when using React.
dev-browser
Fallback browser automation with persistent Chrome state. Use only when Browser Use is unavailable or blocked.
browser-debug-setup
One-time setup for a persistent debug browser on 127.0.0.1:9222 for dev-browser --connect. Use when browser work is needed but no reusable debug browser is running yet.
agent-browser-issue
Open a concise GitHub follow-up for reusable browser-use limitations. Use when browser automation is blocked by a likely tool-side issue that is worth fixing separately, especially for clicks, dropdowns, file inputs, focus traps, or other repeatable agent/browser failures.
hard-cut
Remove a feature completely with no backward compatibility. Use when the user says "hard cut", "rip it out", "delete it", "unship", "kill this feature", or wants dead code removed instead of deprecated. Delete the surface, callers, tests, docs, comments, fallbacks, and stubs.