# api-test-suite-builder

Scans route handlers to generate ready-to-run API test suites for Vitest or Pytest. It builds test matrices for authentication, input validation, status codes, and file uploads.

- skill · `type=skill` · Claude Code · 660 installs · ★ 28733
- Author: Alireza Rezvani
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/alirezarezvani/claude-skills/tree/HEAD/engineering/skills/api-test-suite-builder/SKILL.md
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/skills/api-test-suite-builder

## What it does

The skill detects endpoints across Next.js App Router, Express, FastAPI, and Django REST Framework using `find` and `grep`. Claude Code inspects route handlers, request body schemas, and authentication rules. It produces runnable test files configured for Vitest with Supertest or Pytest with `httpx`.

Generated suites focus on error handling rather than happy paths alone. They test expired tokens, missing headers, incorrect data types, boundary values, and injection payloads. Each endpoint receives checks for HTTP status codes from 400 to 500, file upload limits, and pagination issues. Tests use fixtures instead of hardcoded database identifiers.

Rate limiting tests are placed at the very end of the suite. Running them earlier interferes with parallel test execution by triggering endpoint blocks.

## Install

### Claude Code (native platform)

1. **Plugin marketplace**
In the agent chat (not a shell):
```text
/plugin marketplace add alirezarezvani/claude-skills
```
In the agent chat (not a shell):
```text
/plugin install engineering-advanced-skills@claude-code-skills
```
This installs the whole engineering-advanced-skills plugin with all its skills

2. **Skills CLI (Vercel)**
```bash
npx skills add alirezarezvani/claude-skills --skill api-test-suite-builder -a claude-code
```

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

### Codex

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

### Cursor

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

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install alirezarezvani/claude-skills api-test-suite-builder
```

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

### Gemini CLI

**Platform CLI**
```bash
gemini skills install https://github.com/alirezarezvani/claude-skills --path engineering/skills/api-test-suite-builder
```

### Windsurf (Devin Desktop)

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

### 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/alirezarezvani/claude-skills/tree/HEAD/engineering/skills/api-test-suite-builder/SKILL.md

## When to use it
- generate integration test suites for Next.js or Express route handlers
- create authentication test matrices for expired tokens and missing headers
- verify input validation against boundary values, XSS, and SQL injection payloads
- cover HTTP status codes 400, 401, 403, 404, 422, and 500
- test pagination boundaries and invalid file uploads

## Example prompts
- Scan routes in `src/` and generate Vitest tests for all Express endpoints
- Create a Pytest suite covering auth checks and status codes for FastAPI routes
- Build validation and boundary tests for route handlers under `app/api`

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 99cbd4ea91fe6817.

BEGIN THIRD-PARTY FILE 99cbd4ea91fe6817
````text
---
name: "api-test-suite-builder"
description: "Use when the user asks to generate API tests, create integration test suites, test REST endpoints, or build contract tests."
---

# API Test Suite Builder

**Tier:** POWERFUL
**Category:** Engineering
**Domain:** Testing / API Quality

---

## Overview

Scans API route definitions across frameworks (Next.js App Router, Express, FastAPI, Django REST) and
auto-generates comprehensive test suites covering auth, input validation, error codes, pagination, file
uploads, and rate limiting. Outputs ready-to-run test files for Vitest+Supertest (Node) or Pytest+httpx
(Python).

---

## Core Capabilities

- **Route detection** — scan source files to extract all API endpoints
- **Auth coverage** — valid/invalid/expired tokens, missing auth header
- **Input validation** — missing fields, wrong types, boundary values, injection attempts
- **Error code matrix** — 400/401/403/404/422/500 for each route
- **Pagination** — first/last/empty/oversized pages
- **File uploads** — valid, oversized, wrong MIME type, empty
- **Rate limiting** — burst detection, per-user vs global limits

---

## When to Use

- New API added — generate test scaffold before writing implementation (TDD)
- Legacy API with no tests — scan and generate baseline coverage
- API contract review — verify existing tests match current route definitions
- Pre-release regression check — ensure all routes have at least smoke tests
- Security audit prep — generate adversarial input tests

---

## Route Detection

### Next.js App Router
```bash
# Find all route handlers
find ./app/api -name "route.ts" -o -name "route.js" | sort

# Extract HTTP methods from each route file
grep -rn "export async function\|export function" app/api/**/route.ts | \
  grep -oE "(GET|POST|PUT|PATCH|DELETE|HEAD|OPTIONS)" | sort -u

# Full route map
find ./app/api -name "route.ts" | while read f; do
  route=$(echo $f | sed 's|./app||' | sed 's|/route.ts||')
  methods=$(grep -oE "export (async )?function (GET|POST|PUT|PATCH|DELETE)" "$f" | \
    grep -oE "(GET|POST|PUT|PATCH|DELETE)")
  echo "$methods $route"
done
```

### Express
```bash
# Find all router files
find ./src -name "*.ts" -o -name "*.js" | xargs grep -l "router\.\(get\|post\|put\|delete\|patch\)" 2>/dev/null

# Extract routes with line numbers
grep -rn "router\.\(get\|post\|put\|delete\|patch\)\|app\.\(get\|post\|put\|delete\|patch\)" \
  src/ --include="*.ts" | grep -oE "(get|post|put|delete|patch)\(['\"][^'\"]*['\"]"

# Generate route map
grep -rn "router\.\|app\." src/ --include="*.ts" | \
  grep -oE "\.(get|post|put|delete|patch)\(['\"][^'\"]+['\"]" | \
  sed "s/\.\(.*\)('\(.*\)'/\U\1 \2/"
```

### FastAPI
```bash
# Find all route decorators
grep -rn "@app\.\|@router\." . --include="*.py" | \
````
END THIRD-PARTY FILE 99cbd4ea91fe6817

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