Testing

This is a complete, architecturally-focused guide to software testing. You won't just learn test syntax; you will understand the testing pyramid, how to write testable code, when to use different types of tests, and how to build test suites that give you confidence to ship. We prioritize real-world testing patterns, debugging flaky tests, and production-grade test automation.

• • Testing pyramid: unit, integration, and end-to-end tests
• • Jest and Vitest: matchers, mocks, spies, and async testing
• • React Testing Library: component testing with user-centric approach
• • Playwright: end-to-end testing for web applications
• • Test-driven development (TDD) and behavior-driven development (BDD)
• • Continuous testing in CI/CD pipelines
• • Debugging flaky tests and performance optimization

20 deep-dive theory modules organized into 5 progressive checkpoints — from testing foundations through advanced test automation and production-grade test suites. Each module includes architectural explanations, real-world code examples, and comprehensive quizzes.