testing

A short set of rules for testing software, focused on the public behavior users depend on. TDD, or test-driven development, means writing a failing test before implementing the fix.

In plain words
What is it for?
Use it to guide test-driven fixes, choose suitable mocks, run the project's verification checks, and add regression tests for reported symptoms.
Why use it?
It keeps tests focused and requires verification before a change is considered complete. It also treats flaky tests as failures and requires regression coverage for bugs.

Cursor rule

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/kleosr/kleosrules/testing
Clone the repo
git clone --depth 1 https://github.com/kleosr/kleosrules
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 165 The whole file, excluding the scripts and references it only reads on demand.
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 $0.00000 $0.00165
Opus 5 $0.00000 $0.00082
Sonnet 5 $0.00000 $0.00033
Haiku 4.5 $0.00000 $0.00016

Measured yesterday against content hash b435f6430a8b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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.

shared/rules/testing.mdc · 16 lines

What it actually says

TESTING (THIN)

Cero bloat en tests. Public surface only. Native tools (Read/Grep/Write/StrReplace). House gauntlet first (TOOLCHAIN). Run verify yourself. Fail closed on red. Cite evidence. Bug fix ships regression: <symptom>. Flaky = broken.

PROCEDURE

TDD order, mocks, gauntlet workflows: Read ~/.cursor/skills/testing/SKILL.md before writing or expanding tests.

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 · 16 lines · 0 tokens per session scan A b435f6430a8b

Subscribe to this mod's changes

testing is a cursor rule published in the GitHub repository kleosr/kleosrules (2 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 165 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.