Overview

This section covers the tools that automate software testing across the pyramid — from fast unit tests to full end-to-end browser tests. Each tool includes annotated, runnable By Example tutorials.

Tools in This Section

• Playwright - End-to-end browser automation and testing across Chromium, Firefox, and WebKit, with auto-waiting, tracing, and parallel execution. Includes both By Example and In-the-Field production guides.
• Testing Library - User-centric component and DOM testing that queries the UI the way users do, encouraging accessible, behavior-focused tests.
• Vitest - Fast, Vite-native unit test runner with a Jest-compatible API, watch mode, and built-in coverage.

The Testing Pyramid

These tools map onto the classic testing pyramid:

• Unit tests (most numerous) → Vitest — fast, isolated tests of individual functions and modules.
• Component / integration tests → Testing Library — verify rendered UI behavior and component interaction.
• End-to-end tests (fewest) → Playwright — exercise the whole application through a real browser.

Learning Approach

Each tool provides a By Example tutorial with annotated, runnable code:

• Beginner - Core concepts, first tests, basic assertions
• Intermediate - Realistic suites, fixtures, mocking, and async testing
• Advanced - Complex scenarios, optimization, CI integration, and production patterns

Getting Started

• Testing units and functions? → Vitest
• Testing UI components? → Testing Library
• Testing full user flows in a browser? → Playwright

A healthy suite uses all three: many Vitest unit tests, fewer Testing Library component tests, and a focused set of Playwright end-to-end tests.