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test-master — Claude Code skill: tests, coverage, reports

A skill that walks an agent through writing unit, integration and E2E tests, reading coverage gaps and tracking down flaky failures. Handy when a project has thin test coverage.

Install into Claude Code · Skills CLI (Vercel) All methods and platforms ↓
npx skills add Jeffallan/claude-skills --skill test-master -a claude-code
Open on GitHub

What test-master does

The skill lays out five steps: define what to test, plan the approach, write the tests, run them, then write up findings. When something fails, it asks the agent to tell an assertion error apart from an environment or flakiness problem, fix the cause and run again. Flaky tests get isolated and diagnosed rather than re-run until they pass.

Reference files load on demand: references/unit-testing.md covers Jest, Vitest and pytest, references/integration-testing.md handles API testing with Supertest, and separate files cover E2E strategy, k6 performance work and a security checklist. Report templates, QA methodology, automation patterns, TDD iron laws and testing anti-patterns sit alongside them.

The constraints are strict. Mock external dependencies, never hit real APIs or databases from unit tests, use fixtures instead of production data, assert a specific value rather than truthiness, and skip tests of internal method calls. Reports carry scope, cases with expected outcomes, coverage analysis, findings rated Critical through Low, and concrete fixes.

What it helps with

  • write unit tests for Jest or pytest with readable descriptions
  • find out why a test fails in CI but passes locally
  • close coverage gaps before a release
  • put together a test strategy for a new service
  • run an API against an OWASP checklist

Example prompts for the agent

  • Write unit tests for calculateDiscount, cover boundary values and the negative price case
  • Figure out why checkout.spec.ts fails intermittently and remove the ordering dependency
  • Draft a test plan for the new API and flag the coverage gaps

How to install test-master

1Skills CLI (Vercel)

npx skills add Jeffallan/claude-skills --skill test-master -a claude-code

2Manually: put the files in place

~/.claude/skills/test-master/SKILL.md

Copy the whole skill folder; for one project use .claude/skills/test-master/

Step by step, with commands for each platform: How to install skills in Claude Code: five ways

Questions about test-master

How do I install test-master in Claude Code?

Run npx skills add Jeffallan/claude-skills --skill test-master -a claude-code. The skill file lands at ~/.claude/skills/test-master/SKILL.md.

What does test-master do?

It guides an agent through writing tests, planning a test strategy, analysing coverage and producing reports with findings and fixes. Performance and security testing are covered too.

Which platforms can run test-master?

Besides Claude, install commands exist for Codex, Cursor, GitHub Copilot, Gemini CLI and OpenCode. Each one drops the skill into that tool's own skills directory.

Source text

SKILL.md · MIT
---
name: test-master
description: Generates test files, creates mocking strategies, analyzes code coverage, designs test architectures, and produces test plans and defect reports across functional, performance, and security testing disciplines. Use when writing unit tests, integration tests, or E2E tests; creating test strategies or automation frameworks; analyzing coverage gaps; performance testing with k6 or Artillery; security testing with OWASP methods; debugging flaky tests; or working on QA, regression, test automation, quality gates, shift-left testing, or test maintenance.
license: MIT
metadata:
  author: https://github.com/Jeffallan
  company: https://synergetic.solutions
  version: "1.1.1"
  domain: quality
  triggers: test, testing, QA, unit test, integration test, E2E, coverage, performance test, security test, regression, test strategy, test automation, test framework, quality metrics, defect, exploratory, usability, accessibility, localization, manual testing, shift-left, quality gate, flaky test, test maintenance
  role: specialist
  scope: testing
  output-format: report
  related-skills: fullstack-guardian, playwright-expert, devops-engineer, debugging-wizard, code-reviewer, feature-forge
---

# Test Master

Comprehensive testing specialist ensuring software quality through functional, performance, and security testing.

## Core Workflow

1. **Define scope** — Identify what to test and which testing types apply
2. **Create strategy** — Plan the test approach across functional, performance, and security perspectives
3. **Write tests** — Implement tests with proper assertions (see example below)
4. **Execute** — Run tests and collect results
   - If tests fail: classify the failure (assertion error vs. environment/flakiness), fix root cause, re-run
   - If tests are flaky: isolate ordering dependencies, check async handling, add retry or stabilization logic
5. **Report** — Document findings with severity ratings and actionable fix recommendations
   - Verify coverage targets are met before closing; flag gaps explicitly

## Quick-Start Example

A minimal Jest unit test illustrating the key patterns this skill enforces:

```js
// ✅ Good: meaningful description, specific assertion, isolated dependency
describe('calculateDiscount', () => {
  it('applies 10% discount for premium users', () => {
    const result = calculateDiscount({ price: 100, userTier: 'premium' });
    expect(result).toBe(90); // specific outcome, not just truthy
  });

  it('throws on negative price', () => {
    expect(() => calculateDiscount({ price: -1, userTier: 'standard' }))
      .toThrow('Price must be non-negative');
  });
});
```

Apply the same structure for pytest (`def test_…`, `assert result == expected`) and other frameworks.

## Reference Guide

Load detailed guidance based on context:

<!-- TDD Iron Laws and Testing Anti-Patterns adapted from obra/superpowers by Jesse Vincent (@obra), MIT License -->

| Topic | Reference | Load When |
|-------|-----------|-----------|
| Unit Testing | `references/unit-testing.md` | Jest, Vitest, pytest patterns |
| Integration | `references/integration-testing.md` | API testing, Supertest |
| E2E | `references/e2e-testing.md` | E2E strategy, user flows |
| Performance | `references/performance-testing.md` | k6, load testing |
| Security | `references/security-testing.md` | Security test checklist |
| Reports | `references/test-reports.md` | Report templates, findings |
| QA Methodology | `references/qa-methodology.md` | Manual testing, quality advocacy, shift-left, continuous testing |
| Automation | `references/automation-frameworks.md` | Framework patterns, scaling, maintenance, team enablement |
| TDD Iron Laws | `references/tdd-iron-laws.md` | TDD methodology, test-first development, red-green-refactor |
| Testing Anti-Patterns | `references/testing-anti-patterns.md` | Test review, mock issues, test quality problems |

## Constraints

**MUST DO**
- Test happy paths AND error/edge cases (e.g., empty input, null, boundary values)
- Mock external dependencies — never call real APIs or databases in unit tests
- Use meaningful `it('…')` descriptions that read as plain-English specifications
- Assert specific outcomes (`expect(result).toBe(90)`), not just truthiness
- Run tests in CI/CD; document and remediate coverage gaps

**MUST NOT**
- Skip error-path testing (e.g., don't test only the success branch of a try/catch)
- Use production data in tests — use fixtures or factories instead
- Create order-dependent tests — each test must be independently runnable
- Ignore flaky tests — quarantine and fix them; don't just re-run until green
- Test implementation details (internal method calls) — test observable behaviour

## Output Templates

When creating test plans, provide:
1. Test scope and approach
2. Test cases with expected outcomes
3. Coverage analysis
4. Findings with severity (Critical/High/Medium/Low)
5. Specific fix recommendations

Maintained by [@jeffallan](https://github.com/jeffallan), Principal Consultant at [Synergetic Solutions](https://synergetic.solutions)

[Documentation](https://jeffallan.github.io/claude-skills/skills/quality/test-master/)

© https://github.com/Jeffallan · MIT · Jeffallan/claude-skills

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