React Unit testing

Master React Unit Testing with React Testing Library & Jest

My Journey Into Testing: From Confusion to Clarity

When I first started learning unit testing, I felt completely lost. Every resource I found was either too theoretical or lacked real-world examples. At the beginning of my career, testing wasn't even a priority at the companies I worked for—writing tests felt optional at best.

But then, I joined a company that took unit testing seriously, and suddenly, I had so many questions:

• What should I test?

• Should I test everything?
• How does testing actually work?

At first, it felt overwhelming. But as I dug deeper, I realized something powerful—unit testing isn’t just about catching bugs. It’s about writing reliable, maintainable, and scalable applications with confidence. Without the right guidance, though, getting started can feel intimidating.

That’s exactly why I wrote this book—to give developers like you a clear, structured, and practical approach to testing React applications with React Testing Library (RTL) and Jest.

Stop Guessing, Start Testing!

Are you building React applications but not confident in your tests? Do you struggle with flaky tests, untested components, or unexpected bugs? This book is your ultimate hands-on guide to mastering React Testing Library (RTL) and Jest—ensuring your components work exactly as expected.

What You’ll Learn:

• Fundamentals of React Testing – Understand why testing matters and how to apply the testing pyramid in React applications.

• Setting Up the Testing Environment – Install and configure Jest, React Testing Library (RTL), and TypeScript for seamless development.
• Writing Meaningful Unit Tests – Learn the Arrange, Act, Assert pattern and best practices for writing structured, maintainable tests.
• Testing React Router – Ensure proper navigation, route parameters, and authentication in your components.
• Mocking Functions & API Calls – Master Jest mocking, including function spies, API calls, and module mocking.
• Handling Asynchronous Operations – Work with waitFor, waitForElementToBeRemoved, and fake timers to handle async state updates.
• Testing Hooks & Custom Hooks – Use renderHook, act(), and rerender() to validate state changes and dependencies in custom hooks.
• Testing React Query – Learn how to test query states, cache behavior, background refetching, and mutations in React Query.
• Testing Redux State Management – Write tests for reducers, actions, async thunks, and Redux-connected components.
• Best Practices for Writing Effective Tests – Organize test files, write clean assertions, and troubleshoot flaky tests.
• Enforcing Best Practices with ESLint Rules – Use ESLint for testing to enforce rules and catch common mistakes automatically.
• Test Coverage & Reporting – Generate test coverage reports, optimize testing strategies, and improve test readability.

Who Is This Book For?

Whether you're a beginner learning how to test React apps or an experienced developer refining your testing strategy, this book provides practical, real-world examples that will level up your testing game.

📖 Want a preview? Check out a sample of the book here and see what’s inside before you buy!

📖 Bonus: The book includes exclusive access to a Notion page with fully working React projects and unit tests that you can modify and add to your portfolio!

Don’t just write code—write code you can trust. Get your copy today and start building robust, bug-free React applications!