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beyond-test-coverage: Skill for Claude Code

.claude/skills/test-quality/SKILL.md

test-quality is a skill for Claude Code from rollinsio/beyond-test-coverage. It costs 216 tokens per session (2,341 once invoked), scanned A, original, MIT.

A method for reviewing, strengthening, or creating automated tests so they catch broken behavior and remain valid after code refactoring. Mutation resistance means the tests are checked for whether they detect deliberate changes to the code, rather than only measuring coverage.

In plain words
What is it for?
Use it to audit an existing test suite, repair fragile tests, or generate stronger tests in Python, JavaScript or TypeScript, Go, Kotlin, or Swift. It evaluates tests against a quality scorecard and supports mutation-based checks.
Why use it?
A high coverage percentage does not prove that tests would fail when behavior breaks. This method targets weak assertions and other tests that pass without meaningfully checking the code.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is rollinsio/beyond-test-coverage's own configuration. It tells Claude Code how to work on beyond-test-coverage itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything beyond-test-coverage configures →

Part of the test-quality-tools plugin — 2 skills shipped together

not rated 52repo 4mo ago A scan 216 tokens original MIT
View source ↗ rollinsio/beyond-test-coverage
Reuse

Borrowing it

Nothing to install: this file belongs to rollinsio/beyond-test-coverage. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/rollinsio/beyond-test-coverage/main/.claude/skills/test-quality/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/rollinsio/beyond-test-coverage

Made for: Claude Code.

Or install test-quality-tools, the plugin that ships this one along with the rest of its 2 skills.

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-quality

README.md
[![agentmods](https://agentmods.dev/badge/skills/rollinsio/beyond-test-coverage/test-quality/github.svg)](https://agentmods.dev/skills/rollinsio/beyond-test-coverage/test-quality)
Your own site
<a href="https://agentmods.dev/skills/rollinsio/beyond-test-coverage/test-quality"><img src="https://agentmods.dev/badge/skills/rollinsio/beyond-test-coverage/test-quality/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for test-quality

Your own site · 80×15
<a href="https://agentmods.dev/skills/rollinsio/beyond-test-coverage/test-quality"><img src="https://agentmods.dev/badge/skills/rollinsio/beyond-test-coverage/test-quality.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 216 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,341 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00216 $0.02341
Opus 5.5 $0.00086 $0.00936
Sonnet 5.5 $0.00043 $0.00468
Haiku 4.5 $0.00022 $0.00234

Measured 2mo ago against content hash 0e0e954b543e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

test-quality 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 2mo ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/score.py, tests/test_score.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

.claude/skills/test-quality/SKILL.md · 166 lines

How it starts

The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.

test-quality

Bring a target's tests up to a durable-quality bar. "Quality" means tests that fail when behavior breaks and survive when it's only refactored — the opposite of coverage-chasing suites that hit 100% yet catch nothing.

This skill encodes the result of a controlled experiment: pointing test generation at a multi-axis quality scorecard (rather than a coverage number) produced suites that beat human-written baselines on the auto-countable axes in 9 of 9 Python suites (8 of 9 with the model held fixed — the rubric, not the model, drove the gain). The two reference docs are that experiment's distilled output:

  • references/quality-contract.md — 10 anti-fragility rules, each with the repair.
  • references/scorecard.md — the scoring axes, the improvement gate, the stop condition.
  • scripts/score.py — measures the auto-countable axes for a suite in any supported language (Python/pytest, JS/TS, Go, Kotlin, Swift).

Read both reference docs before starting. They are the substance; this file is the procedure.

Core principle

Coverage is a floor, not a goal. Once the suite is at or above its starting coverage, more coverage doesn't count as improvement. What counts is moving the quality axes: fewer fragility patterns, more rigor signals, less real mocking, better LOC efficiency — with every test traceable to a user-observable contract.

Inputs

  • Target (required): a module/package to test, an existing test file/dir to improve, or both. If the user didn't specify, ask what to target.
  • Test command (auto-detect, confirm if unsure): how to run the suite with coverage. Detect from the project's config/manifest, then by stack:
    • pytest: python -m pytest <tests> --cov=<src> --cov-branch
    • Jest: npx jest --coverage · Vitest: npx vitest run --coverage
    • Mocha: npx c8 --check-coverage mocha (c8/nyc for coverage)
    • Go: go test -cover -coverprofile=cover.out ./... && go tool cover -func=cover.out
    • Kotlin: ./gradlew test (coverage via the JaCoCo/Kover plugin if configured)
    • Swift: swift test --enable-code-coverage (SwiftPM) or xcodebuild test (Xcode) Read pyproject.toml/pytest.ini, package.json(scripts.test, jest/vitest config), go.mod, build.gradle(.kts)/settings.gradle, Package.swift, Makefile to find the project's real command — prefer it over the defaults above.

Read the full file on GitHub · 166 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2mo ago First seen · 166 lines · 216 tokens per session scan A 0e0e954b543e

Subscribe to this mod's changes

test-quality is a skill published in the GitHub repository rollinsio/beyond-test-coverage (52 stars, last pushed 4mo ago), licensed MIT. It adds 216 tokens to every session and 2,341 once invoked, about $0.0009 per session on Opus 5.5. 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.

LLMTestingUnit testingbenchmarkclaudecode-qualitymochapytest
Related

test-quality compared with skills from other repositories

test-quality next to 6 skills from other repositories
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