# test-coverage

Use this reference to assess what an existing test suite exercises across code, mutations, requirements, and APIs. It is for analysis after tests have been written.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 623 installs · ★ 1787
- Author: NeoLabHQ
- License: GPL-3.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/NeoLabHQ/context-engineering-kit/tree/HEAD/skills/test-coverage/SKILL.md
- Updated: 2026-08-26
- HTML: https://affpapa.org/en/nevibecode/skills/neolabhq-test-coverage

## What it does

\`test-coverage` is a reference for examining an existing test suite. It helps you choose among code instrumentation, mutation analysis, requirement traceability, API and integration checks, and specification-domain analysis.

Each approach measures a different signal and has blind spots. Executing a line does not show that a test asserts the right result or would catch a defect. Treat coverage as evidence about what tests touch, not as a verdict on their quality.

This is guidance for measuring tests that already exist, not for designing a test strategy. Structural reports record executed code elements; mutation analysis reruns the suite against altered source. Those methods assess the suite rather than create new tests.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add NeoLabHQ/context-engineering-kit --skill test-coverage -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/test-coverage/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/test-coverage/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add NeoLabHQ/context-engineering-kit --skill test-coverage -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/test-coverage/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add NeoLabHQ/context-engineering-kit --skill test-coverage -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/test-coverage/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install NeoLabHQ/context-engineering-kit test-coverage
```

2. **Manually: put the files in place**
- File: `.github/skills/test-coverage/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add NeoLabHQ/context-engineering-kit --skill test-coverage -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/NeoLabHQ/context-engineering-kit --path skills/test-coverage
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/test-coverage/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add NeoLabHQ/context-engineering-kit --skill test-coverage -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/NeoLabHQ/context-engineering-kit/tree/HEAD/skills/test-coverage/SKILL.md

## When to use it
- Choose a coverage method for an existing test suite
- Find code branches that tests never execute
- Check whether tests catch deliberately introduced faults
- Trace tests to acceptance criteria
- Inspect which API interactions the suite exercises

## Example prompts
- Review what my existing tests cover and explain what the code coverage percentage misses.
- Explain how mutation analysis can show whether this suite catches faults.
- Compare these tests with the requirements and identify criteria without a verifying test.

## Similar
- [improve-codebase-architecture](https://affpapa.org/en/nevibecode/skills/improve-codebase-architecture.md) — skill · 1163035 installs
- [design-taste-frontend](https://affpapa.org/en/nevibecode/skills/design-taste-frontend.md) — skill · 678700 installs
- [tdd](https://affpapa.org/en/nevibecode/skills/tdd.md) — skill · 1141062 installs
- [skill-creator](https://affpapa.org/en/nevibecode/skills/skill-creator.md) — skill · 414180 installs
- [agent-browser](https://affpapa.org/en/nevibecode/skills/vercel-labs-agent-browser.md) — skill · 1200000 installs
- [prototype](https://affpapa.org/en/nevibecode/skills/prototype.md) — skill · 986201 installs

## Other versions with the same name
- [test-coverage · cognitedata](https://affpapa.org/en/nevibecode/skills/test-coverage.md) — 1900 installs

From the same set: [neolabhq/context-engineering-kit](https://affpapa.org/en/nevibecode/by/neolabhq/context-engineering-kit.md) — 64 cards

---
NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md