api-test-suite-builder

API Test Suite Builder

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

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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).

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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

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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

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Route Detection

Next.js App Router

# 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

# 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/"