test

test is a cursor rule for Cursor from pylarco/diff-apply. It costs 183 tokens per session, scanned A, original, MIT.

A set of testing rules for Bun’s built-in test runner. It requires isolated tests, thorough coverage of the real algorithm, and test files in test/unit or test/e2e.

In plain words
What is it for?
Writing, organizing, and repairing unit or end-to-end tests in a Bun project.
Why use it?
It helps prevent fragile tests, leftover state, and fixes that weaken tests instead of correcting the program.

Cursor rule for Cursor

Install

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.

agentmods
npx agentmods add rules/pylarco/diff-apply/test
Clone the repo
git clone --depth 1 https://github.com/pylarco/diff-apply

Made for: Cursor.

Wrote 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.

agentmods badge for test

README.md
[![agentmods](https://agentmods.dev/badge/rules/pylarco/diff-apply/test.svg)](https://agentmods.dev/rules/pylarco/diff-apply/test)
Your own site
<a href="https://agentmods.dev/rules/pylarco/diff-apply/test"><img src="https://agentmods.dev/badge/rules/pylarco/diff-apply/test.svg" alt="Measured on agentmods" height="20"></a>
Per session 183 This file is loaded in full into every session.
When invoked 183 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00183 $0.00183
Opus 5 $0.00092 $0.00092
Sonnet 5 $0.00037 $0.00037
Haiku 4.5 $0.00018 $0.00018

Measured 2d ago against content hash fe753d6f8ecc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test 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.

.cursor/rules/test.mdc · 14 lines

What it actually says

  1. while addressing fail tests, always have a mindset that there must be main program core error to fix rather than make test less strict!!
  2. Test cases should be isolated and clean no left over even on sigterm
  3. Test should use bun:test describe,it,afterAll,beforeAll,afterEach,beforeEach without mock
  4. Create challenging, thorough test cases that fully verify implementation
  5. Test cases should match expected requirements
  6. Do not create test of tricks, simulation, stub, mock, etc. you should produce code of real algorithm
  7. Do not create any new file for helper,script etc. just do what prompted.
  8. test files should only be located outside src at test/unit or test/e2e
  9. test should use/modify test/test.util.ts for reusability
Changes

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.

  1. 2d ago First seen · 14 lines · 183 tokens per session scan A fe753d6f8ecc

Subscribe to this mod's changes

test is a cursor rule published in the GitHub repository pylarco/diff-apply (10 stars, last pushed 1y ago), licensed MIT. It adds 183 tokens to every session, about $0.0009 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 2026-09-02.