Agent skill

Test Quality Analysis

Detect test smells, overmocking, flaky tests, and coverage issues.

MITAuto-check: notesTesting & QA

Install Test Quality Analysis

skills CLI

$ npx skills add secondsky/claude-skills --skill test-quality-analysis -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills test-quality-analysis --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/test-quality-analysis/skills/test-quality-analysis .claude/skills/test-quality-analysis && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "test-quality-analysis" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis into .claude/skills/test-quality-analysis/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "test-quality-analysis", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add secondsky/claude-skills --skill test-quality-analysis -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills test-quality-analysis --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/test-quality-analysis/skills/test-quality-analysis .agents/skills/test-quality-analysis && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "test-quality-analysis" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis into .agents/skills/test-quality-analysis/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "test-quality-analysis", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add secondsky/claude-skills --skill test-quality-analysis -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills test-quality-analysis --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/test-quality-analysis/skills/test-quality-analysis .cursor/skills/test-quality-analysis && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "test-quality-analysis" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis into .cursor/skills/test-quality-analysis/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "test-quality-analysis", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/secondsky/claude-skills.git --path plugins/test-quality-analysis/skills/test-quality-analysis

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add secondsky/claude-skills --skill test-quality-analysis -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills test-quality-analysis --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/test-quality-analysis/skills/test-quality-analysis .gemini/skills/test-quality-analysis && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "test-quality-analysis" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis into .gemini/skills/test-quality-analysis/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "test-quality-analysis", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install secondsky/claude-skills test-quality-analysis

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add secondsky/claude-skills --skill test-quality-analysis -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/test-quality-analysis/skills/test-quality-analysis .github/skills/test-quality-analysis && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "test-quality-analysis" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis into .github/skills/test-quality-analysis/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "test-quality-analysis", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add secondsky/claude-skills --skill test-quality-analysis -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills test-quality-analysis --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/test-quality-analysis/skills/test-quality-analysis .opencode/skills/test-quality-analysis && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "test-quality-analysis" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/test-quality-analysis/skills/test-quality-analysis into .opencode/skills/test-quality-analysis/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "test-quality-analysis", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: test-quality-analysis
GitHub stars: 227
Token cost: ~1.2k tokens
SKILL.md length: 248 words
Files: 1
Skills in repo: 169
Repo updated: Sep 28, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Detect test smells, overmocking, flaky tests, and coverage issues.

Reviewing tests
SKILL.md covers Core Dimensions, Test Smells, Analysis Tools and Best Practices Checklist, plus 3 more sections
Calls bun and uv
Improving test quality

What it does

Test Quality Analysis is an agent skill from secondsky/claude-skills. Detect test smells, overmocking, flaky tests, and coverage issues. Analyze test effectiveness, maintainability, and reliability. Use when reviewing tests or improving test quality.

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Testing & QA, covering Failing and flaky tests. The repository describes itself as: Production-ready skills for Claude Code CLI - Cloudflare, React, Tailwind v4, and AI integrations. The licence is MIT.

When your agent uses it

Reviewing tests
Improving test quality

Example prompts

“/test-quality-analysis”

Requirements

Pre-approved tools (allowed-tools): Bash, Read, Edit, Write, Grep, Glob, TodoWrite

What it can do on your machine

Read from SKILL.md and the folder at commit 8837836. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
- Bash
- Read
- Edit
- Write
- Grep
- Glob
- TodoWrite
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- bun
- uv
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use uv, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Test Quality Analysis loads about 1.2k tokens when it runs. Until then it costs about 51 tokens; SKILL.md has 248 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~51
When it runs · the whole SKILL.md, loaded when a task matches: ~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NotePre-approves every shell command (allowed-tools: Bash)SKILL.md
```
allowed-tools: Bash, Read, Edit, Write, Grep, Glob, TodoWrite
```

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from secondsky/claude-skills at commit 8837836, republished under its MIT licence (© secondsky). 248 words, ~1,194 tokens.

Download SKILL.mdSave it as .claude/skills/test-quality-analysis/SKILL.md (or your agent's skills folder).

name: test-quality-analysis
description: Detect test smells, overmocking, flaky tests, and coverage issues. Analyze test effectiveness, maintainability, and reliability. Use when reviewing tests or improving test quality.
allowed-tools: Bash, Read, Edit, Write, Grep, Glob, TodoWrite
license: MIT

Test Quality Analysis

Expert knowledge for analyzing and improving test quality - detecting test smells, overmocking, insufficient coverage, and testing anti-patterns.

Core Dimensions

Correctness: Tests verify the right behavior
Reliability: Tests are deterministic, not flaky
Maintainability: Tests are easy to understand
Performance: Tests run quickly
Coverage: Tests cover critical code paths
Isolation: Tests don't depend on external state

Test Smells

Overmocking

Problem: Mocking too many dependencies makes tests fragile.

typescript

// ❌ BAD: Overmocked
test('calculate total', () => {
  const mockAdd = vi.fn(() => 10)
  const mockMultiply = vi.fn(() => 20)
  // Testing implementation, not behavior
})

// ✅ GOOD: Mock only external dependencies
test('calculate order total', () => {
  const mockPricingAPI = vi.fn(() => ({ tax: 0.1 }))
  const total = calculateTotal(order, mockPricingAPI)
  expect(total).toBe(38)
})

Detection: More than 3-4 mocks, mocking pure functions, complex mock setup.

Fix: Mock only I/O boundaries (APIs, databases, filesystem).

Fragile Tests

Problem: Tests break with unrelated code changes.

typescript

// ❌ BAD: Tests implementation details
await page.locator('.form-container > div:nth-child(2) > button').click()

// ✅ GOOD: Semantic selector
await page.getByRole('button', { name: 'Submit' }).click()

Flaky Tests

Problem: Tests pass or fail non-deterministically.

typescript

// ❌ BAD: Race condition
test('loads data', async () => {
  fetchData()
  await new Promise(resolve => setTimeout(resolve, 1000))
  expect(data).toBeDefined()
})

// ✅ GOOD: Proper async handling
test('loads data', async () => {
  const data = await fetchData()
  expect(data).toBeDefined()
})

Poor Assertions

typescript

// ❌ BAD: Weak assertion
test('returns users', async () => {
  const users = await getUsers()
  expect(users).toBeDefined() // Too vague!
})

// ✅ GOOD: Strong, specific assertions
test('creates user with correct attributes', async () => {
  const user = await createUser({ name: 'John' })
  expect(user).toMatchObject({
    id: expect.any(Number),
    name: 'John',
  })
})

Analysis Tools

bash

# Vitest coverage (prefer bun)
bun test --coverage
open coverage/index.html

# Check thresholds
bun test --coverage --coverage.thresholds.lines=80

# pytest-cov (Python)
uv run pytest --cov --cov-report=html
open htmlcov/index.html

Best Practices Checklist

Unit Test Quality (FIRST)

Fast: Tests run in milliseconds
Isolated: No dependencies between tests
Repeatable: Same results every time
Self-validating: Clear pass/fail
Timely: Written alongside code

Mock Guidelines

Mock only external dependencies
Don't mock business logic or pure functions
Use real implementations when possible
Limit to 3-4 mocks per test maximum

Coverage Goals

80%+ line coverage for business logic
100% for critical paths (auth, payment)
All error paths tested
Boundary conditions tested

Test Structure (AAA Pattern)

typescript

test('user registration', async () => {
  // Arrange
  const userData = { email: 'user@example.com' }

  // Act
  const user = await registerUser(userData)

  // Assert
  expect(user.email).toBe('user@example.com')
})

Code Review Checklist

Tests verify behavior, not implementation
Assertions are specific and meaningful
No flaky tests (timing, ordering issues)
Proper async/await usage
Test names clearly describe behavior
Minimal code duplication
Critical paths have tests
Both happy path and error cases covered

Common Anti-Patterns

Testing Implementation Details

typescript

// ❌ BAD
const spy = vi.spyOn(Math, 'sqrt')
calculateDistance()
expect(spy).toHaveBeenCalled() // Testing how, not what

// ✅ GOOD
const distance = calculateDistance({ x: 0, y: 0 }, { x: 3, y: 4 })
expect(distance).toBe(5) // Testing output

Mocking Too Much

typescript

// ❌ BAD
const mockAdd = vi.fn((a, b) => a + b)

// ✅ GOOD: Use real implementations
import { add } from './utils'
// Only mock external services
const mockPaymentGateway = vi.fn()

Files

Just SKILL.md in plugins/test-quality-analysis/skills/test-quality-analysis of secondsky/claude-skills.

Open the folder on GitHubat commit 8837836

Compare with similar skills

Test Quality Analysis next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Test Quality Analysis compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Test Quality Analysis this skillsecondsky/claude-skills	227	—	~1.2k	Automated safety check: Notes	MIT	9 days ago
Swig Testswig/swig	6.3k	—	~2.3k	Automated safety check: Pass	Custom licence	today
Dynamo Jira TicketDynamoDS/Dynamo	2k	—	~1.1k	Automated safety check: Pass	Apache-2.0	today
Fix Ready PRsfastrepl/anarlog	9.4k	—	~1.4k	Automated safety check: Pass	MIT	today
Trx Analysismicrosoft/vstest	969	—	~1.8k	Automated safety check: Pass	MIT	yesterday
Wioworkersio/skills	180	—	~5.8k	Automated safety check: Pass	MIT	2 mo ago

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Questions about Test Quality Analysis

What does Test Quality Analysis do?

Detect test smells, overmocking, flaky tests, and coverage issues. Test Quality Analysis is an agent skill from secondsky/claude-skills. Detect test smells, overmocking, flaky tests, and coverage issues.

When should I use Test Quality Analysis?

Test Quality Analysis fits situations like: reviewing tests; improving test quality.

How do I install Test Quality Analysis in Claude Code?

Run `npx skills add secondsky/claude-skills --skill test-quality-analysis -a claude-code`. Or copy the skill folder (plugins/test-quality-analysis/skills/test-quality-analysis in secondsky/claude-skills) into .claude/skills/test-quality-analysis in your project. Claude Code loads it when a task matches its description.

How do I install Test Quality Analysis in Codex?

Run `npx skills add secondsky/claude-skills --skill test-quality-analysis -a codex`. Or copy the skill folder (plugins/test-quality-analysis/skills/test-quality-analysis in secondsky/claude-skills) into .agents/skills/test-quality-analysis in your project. Codex loads it when a task matches its description.

Can I use Test Quality Analysis in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add secondsky/claude-skills --skill test-quality-analysis -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/test-quality-analysis, .gemini/skills/test-quality-analysis, .github/skills/test-quality-analysis and .opencode/skills/test-quality-analysis in your project.

What does Test Quality Analysis need to run?

Going by SKILL.md and its folder, Test Quality Analysis needs the command-line tools its instructions call (bun and uv). Its frontmatter pre-approves these tools: Bash, Read, Edit, Write, Grep, Glob, TodoWrite.

Does Test Quality Analysis access the network?

SKILL.md contains no URLs. Its commands use uv, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Test Quality Analysis safe to install?

Our automated static check of SKILL.md found notes only (pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.

What licence does Test Quality Analysis use?

Test Quality Analysis is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Test Quality Analysis use?

About 1.2k tokens (SKILL.md is roughly 4.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Test Quality Analysis?

Skills that share tags, products or a category with Test Quality Analysis: Swig Test (swig/swig, 6.3k stars), Dynamo Jira Ticket (DynamoDS/Dynamo, 2k stars), Fix Ready PRs (fastrepl/anarlog, 9.4k stars) and Trx Analysis (microsoft/vstest, 969 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Test Quality Analysis?

secondsky (a GitHub user) maintains it in secondsky/claude-skills, which has 227 GitHub stars. The repository holds 169 skills in this directory. The repository was last updated on September 28, 2026.

Source: secondsky/claude-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Test Quality Analysis

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Test Quality Analysis

Core Dimensions

Test Smells

Overmocking

Fragile Tests

Flaky Tests

Poor Assertions

Analysis Tools

Best Practices Checklist

Unit Test Quality (FIRST)

Mock Guidelines

Coverage Goals

Test Structure (AAA Pattern)

Code Review Checklist

Common Anti-Patterns

Testing Implementation Details

Mocking Too Much

See Also

Files

Compare with similar skills

Similar skills

More from secondsky/claude-skills

Related

Questions about Test Quality Analysis