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/tonyghiani/ai-essentials/testing-stylegit clone --depth 1 https://github.com/tonyghiani/ai-essentialsWhat 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 | $0.00000 | $0.00485 |
| Opus 5 | $0.00000 | $0.00243 |
| Sonnet 5 | $0.00000 | $0.00097 |
| Haiku 4.5 | $0.00000 | $0.00049 |
Grade A, and why
testing-style 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 2d 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.
What it actually says
Project conventions win. Read the neighbouring tests first.
Placement
❌ tests/checklist_card.test.tsx
✅ checklist_card.tsx + checklist_card.test.tsx
Colocated beside the source. No __tests__ directories.
describe('<ExportedSymbol>') at the top level, one nested describe per method or option group.
Naming
❌ it('should throw a 409 error when the state blocks activity') ✅ it('throws a 409 error in a state that blocks activity') Declarative third person. No "should".
Mocking
✅ const makeService = (state: TMaintenanceState) =>
({ getState: jest.fn(async () => state) } as unknown as IMaintenanceService);
Services and anything stateful get a hand-rolled fake that round-trips state: a client that throws
NotFound until create, an API that tracks enabled so pause then resume behaves. Cast at the seam
with as unknown as T, and JSDoc each option field.
✅ jest.mock('../../hooks/use_kibana', () => ({ useKibana: () => stub }));
jest.mock is for module-mocking your own hooks in component tests. Not for services.
✅ const REQUEST = {} as IRequest; Shared fixtures are SCREAMING_SNAKE module constants.
Variables get full names here too: rulesClient, not rc.
Assertions
❌ expect(result).toMatchSnapshot();
✅ await expect(assertNotPaused({ service, request: REQUEST })).rejects.toMatchObject({ statusCode: 409 });
✅ expect(service.getStatus).not.toHaveBeenCalled();
Concrete values, or expect.objectContaining. Snapshots only where a tool generates them.
Negative assertions pin what must not happen, such as proving a guard took the cheap read.
What to test
Edge cases and contracts first; the happy path only as their setup. Idempotency, retry after partial failure, a missing dependency, out-of-band state change, inverted ranges, and the exact boundary (299ms, then 300ms).
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.
- 2d ago First seen · 55 lines · 0 tokens per session scan A 635c757bdd06
testing-style is a cursor rule published in the GitHub repository tonyghiani/ai-essentials (6 stars, last pushed 24d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 485 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 2026-08-31.
Other cursor rules, from other repositories
angular-20
This rule provides comprehensive best practices and coding standards for Angular development, focusing on modern TypeScript, standalone components, signals, and performance optimizations.
dev-standard
Apache Superset development standards and guidelines for Cursor IDE.
cli-error-handling
CLI command error handling patterns.
prefer-direct-imports-over-module-mocks
Prefer extracting a testable core over vi.mock / vi.resetModules when unit tests need to reach production logic entangled with config, env, or singletons.
control-plane-descriptors
Control plane descriptor and instance implementation patterns.
family-instance-domain-actions
Family instance domain action implementation patterns.