agent-rules testing.instructions.md

Testing rules for Node.js applications, including clear test names and the arrange-act-assert pattern: set up data, perform an action, then check the result. They specify Node.js's built-in test tools, modern JavaScript modules, and asynchronous test practices.

In plain words
What is it for?
Use them when creating, updating, refactoring, or reviewing tests in JavaScript and TypeScript Node.js projects.
Why use it?
They give coding agents consistent standards for writing and changing tests. This reduces unclear test structure and avoids introducing unsupported testing libraries or code styles.

Instructions file for GitHub Copilot

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 instructions/lirantal/agent-rules/testing
Clone the repo
git clone --depth 1 https://github.com/lirantal/agent-rules

Made for: GitHub Copilot.

Per session 6,713 This file is loaded in full into every session.
When invoked 6,713 The same file — it is already loaded in full.
Security scan A 1 finding. 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 $0.06713 $0.06713
Opus 5 $0.03356 $0.03356
Sonnet 5 $0.01343 $0.01343
Haiku 4.5 $0.00671 $0.00671

Measured yesterday against content hash b04fff89ddc7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-rules testing.instructions.md scanned grade A with 1 finding 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

To test command-line tools, use `node:child_process` to execute the CLI and assert on its output. For asynchronous operations where you need to capture streamed output or handle more complex interactions, using `exec` wi
.github/instructions/testing.instructions.md · 715 lines

How it starts

The opening of the file, as written. The whole thing — 715 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Testing Guidelines for Node.js applications

This document outlines the rules and guidelines for AI agents generating test code for modern Node.js applications.

The following are project tests code standards, principles and strategy for for JavaScript and TypeScript projects that you should apply and follow if you are working on a task related to writing tests, updating existing tests, or overall refactoring and making changes to test code.

General Testing Principles

Guiding Principles

  1. Modern Node.js: All test code must be compatible with Node.js version 22 and above.
  2. Latest JavaScript: Utilize the latest JavaScript features (ES2022 and beyond), including top-level await and modern syntax.
  3. Built-in Tools: Exclusively use the built-in Node.js test runner (node:test) and assertion library (node:assert). No third-party testing frameworks (e.g., Jest, Mocha, Chai) should be used.
  4. ES Modules: All code should be written using ES Modules (import/export). CommonJS (require) should be avoided.
  5. Asynchronous Focus: Tests should be written with an async-first mindset, effectively handling promises and asynchronous operations.
  6. Clarity and Readability: Tests should be easy to understand. Use descriptive names for describe blocks and test cases.

Descriptive Test Naming (Three-Part Structure)

A well-named test clearly communicates its purpose, making test reports more informative and debugging easier for anyone, regardless of their familiarity with the codebase. Adopt a three-part structure for your test names:

  1. What is being tested? (The unit under test, e.g., ProductsService.addNewProduct)
  2. Under what circumstances/scenario? (The specific conditions, e.g., no price is passed to the method)
  3. What is the expected result? (The outcome, e.g., the new product is not approved)

This structure ensures that a failing test immediately tells you what broke, when it broke, and what the expected behavior was.

Read the full file on GitHub · 715 lines

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. yesterday First seen · 715 lines · 6,713 tokens per session scan A b04fff89ddc7

Subscribe to this mod's changes

agent-rules testing.instructions.md is an instructions file published in the GitHub repository lirantal/agent-rules (62 stars, last pushed 14d ago), licensed Apache-2.0. It adds 6,713 tokens to every session, about $0.0336 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.