Testing

Test Strategy

Respondeo uses a combination of unit tests, integration tests, and load tests to ensure reliability and performance.

Unit Tests

Unit tests cover individual functions and components:

• Validation schemas — Zod schema edge cases
• Permission helpers — RBAC functions
• Utility functions — Data transformations

Run unit tests:

bun test

Integration Tests

Integration tests verify end-to-end functionality:

• Server actions — Quiz creation, attempt submission
• API routes — All endpoints with authentication
• Database operations — CRUD operations

Load Tests

Load tests simulate high-traffic scenarios using k6.

Load Test Results

The app has been tested to sustain 5000 concurrent users with 0% error rate.

Latest Results (January 4, 2026)

Performance Optimizations

The following optimizations enabled this performance level:

1. Redis/Valkey caching — 5-10 minute TTL on read-heavy data
2. PostgreSQL tuning — Increased connections and memory
3. Cached quiz data for attempts — Eliminates 3 DB queries per attempt

Endpoint Latency

Notes:

• Median latencies are excellent (~10ms) thanks to caching
• p95+ latencies are elevated under peak load but acceptable
• Write path (attempt submission) has highest latency as expected

Comparison: Before vs After Caching

Running Load Tests

Prerequisites

Install k6:

# macOS
brew install k6

# Linux
sudo gpg -k
sudo gpg --no-default-keyring --keyring /usr/share/keyrings/k6-archive-keyring.gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C5AD17C747E3415A3642D57D77C6C491D6AC1D69
echo "deb [signed-by=/usr/share/keyrings/k6-archive-keyring.gpg] https://dl.k6.io/deb stable main" | sudo tee /etc/apt/sources.list.d/k6.list
sudo apt-get update
sudo apt-get install k6

# Windows
choco install k6

Run Load Test

# Start the app
docker compose up -d
bun run dev

# In another terminal
bun run loadtest

The load test script is located at apps/web/tests/loadtest.js.

Test Scenarios

The load test simulates three user types:

1. Browsers (60%) — View quiz list and details
2. Players (30%) — Play quizzes and submit attempts
3. Spectators (10%) — View leaderboards

Customizing Load Tests

Edit apps/web/tests/loadtest.js:

export const options = {
  stages: [
    { duration: "30s", target: 100 }, // Ramp up to 100 users
    { duration: "1m", target: 100 }, // Stay at 100 users
    { duration: "30s", target: 0 }, // Ramp down to 0
  ],
  thresholds: {
    http_req_failed: ["rate<0.01"], // <1% errors
    http_req_duration: ["p(95)<1000"], // 95% requests <1s
  },
};

Performance Monitoring

Database

Monitor PostgreSQL performance:

docker compose exec db psql -U quiz_app -c "SELECT * FROM pg_stat_activity;"

Cache

Monitor Redis/Valkey:

docker compose exec valkey redis-cli INFO stats
docker compose exec valkey redis-cli INFO memory

Application

Next.js performance monitoring is available through:

• Vercel Analytics (if deployed on Vercel)
• Custom logging in server actions and API routes

Next Steps

• Architecture — System architecture
• Caching Guide — Caching configuration
• Database Guide — Database optimization