Testing for Builders
Most developers either write no tests and regress constantly, or write obsessively many tests that break with every refactor. The discipline is knowing which tests to write, at which layer, and how to make them resilient to change. This course covers the full testing pyramid with Vitest, React Testing Library, and Playwright — with a practical emphasis on what is worth testing and what is not.
What you will learn
Course outline
Free — no account needed
Why Testing Is Worth It
The real return on test investment — and the tests that actually prevent regressions
Unit Testing with Vitest
Write fast, clear unit tests for your TypeScript functions — with Vitest's Jest-compatible API
Testing React Components
Test component behaviour, not implementation — write tests that survive refactors
Full course — $49 one-time
Integration Tests and Databases
Test your API routes against a real database — catch the bugs unit tests cannot see
What Not to Test
The tests that waste your time — and why deleting bad tests improves your test suite
E2E Testing with Playwright
Automate a real browser to test your most critical user journeys — sign up, pay, use the product
Test-Driven Development in Practice
Write the test first — a practical TDD workflow that improves design and catches regressions from day one
CI Testing Pipelines
Run your entire test suite automatically on every pull request — so nothing broken ever reaches main
Get the full course
All 8 lessons — unit, integration, E2E, TDD, and CI testing. Lifetime access.