Ultimate React Testing with Jest

Write clean, confident React tests that eliminate bugs before they reach users.

Key Features
● End-to-end React testing with Jest and React Testing Library.
● Hands-on coverage of hooks, async flows, Redux, routing, and CI.
● Modern testing strategies using Jest, RTL, MSW, and real scenarios.

Book Description
Ultimate React Testing with Jest uses Jest as the foundation to introduce practical, production-ready frontend testing that fits the pace of real engineering teams.

The book begins by understanding why testing matters and how to approach it the right way, then moves into testing React applications incrementally. Early chapters focus on testing components and user interactions, helping you think in terms of behavior, rather than implementation. As you progress, you will learn how to test hooks, handle asynchronous flows, and manage complex UI states with confidence. It then dives deeper into real-world application concerns, covering state management with Redux and Context, routing, authentication flows, and side effects.

In the final chapters, you will bring everything together by measuring test coverage, integrating tests into CI/CD pipelines, and designing test suites that remain stable as applications evolve. Hence, whether you are maintaining legacy code or building new React products from scratch, this book equips you to write tests you can trust—and ship React applications with confidence, speed, and clarity.

What you will learn
● Design reliable React tests using Jest that remain stable as applications scale.
● Test hooks, async logic, and complex UI flows with confidence.
● Use React Testing Library to test UI behavior from the user perspective.
● Apply Jest best practices for mocking, coverage, and test performance.
● Validate Redux, Context, and side effects using real-world patterns.
● Integrate automated testing into CI/CD pipelines for safer releases.
● Build future-proof test suites using RTL and Mock Service Worker.

1. Introduction to Testing
2. Jest Fundamentals
3. Introduction to React and React Testing Library
4. Advanced Testing Techniques
5. Testing React Hooks and Asynchronous Operations
6. Redux Thunk and Context
7. Jest Best Practices and Capabilities
8. Testing Real-World React Applications
9. Jest Coverage and CI/CD Integration
10. Practical Exercises and Challenges
11. Future-proof Testing with RTL
12. Mastering Mock Service Worker in Jest: Patterns, Best Practices, and Pitfalls
13. Conclusion and Next Steps
Index

Sreejith Salgunanis a Senior Frontend Engineer specializing in React, TypeScript, Jest, and React Testing Library. He builds large-scale, production-ready applications and helps teams write reliable and maintainable tests. His expertise spans micro-frontends, Redux, async flows, and modern React testing strategies.

About the Technical Reviewer
Anjani Kumar Varma is an Associate at Cognizant Technology Solutions, where he has spent nearly four years architecting and developing high-performance React-based applications. Currently, he partners with a leading retail client to deliver scalable, maintainable digital experiences for millions of users. Anjani’s technical expertise spans the React ecosystem, including Redux, React Testing Library (RTL), Jest, and Module Federation, alongside Adobe Experience Manager. He has a proven track record of optimizing application performance through lazy loading, tree-shaking, and the remediation of memory leaks. As a key member of the core governance team, Anjani ensures code quality across multiple repositories. He has championed several process improvements, such as implementing pre-commit hooks to enforce optional chaining and utilizing Webpack configurations to automate the removal of console logs in production builds. Beyond core development, Anjani is instrumental in driving business intelligence. By implementing Adobe tagging and Quantum metrics, he has significantly enhanced the client’s ability to capture user behavior data. His work focuses on building reliable, analytics-ready applications that translate complex technical data into invaluable business insights.