Mastering Moq: Practical Mocking Techniques and Unit-Testing Patterns for .NET Developers is a hands-on, professional guide that equips .NET engineers and testers with the theory and practical skills needed to write robust, maintainable unit tests. Grounded in core testing principles and Test-Driven Development, the book explains the role of mocking frameworks and demystifies Moq's expressive API and design philosophy to help readers isolate dependencies, reason about behavior, and confidently drive design through tests.

Through clear, real-world examples, the book walks readers from fundamental test doubles to advanced mocking scenarios: configuring strict, loose, and partial mocks; handling asynchronous code and event simulation; composing complex object graphs; and leveraging LINQ-based setup patterns. It also addresses common technical challenges—testing static, sealed, or non-virtual members—while showing how Moq integrates into CI/CD pipelines and scales across ASP.NET Core applications, microservices, and distributed systems, with practical guidance for xUnit, MSTest, and NUnit users.

Beyond mechanics, Mastering Moq teaches sustainable testing practices and patterns for building stable suites: test organization, fixture management, reusable setup helpers, and anti-pattern avoidance. Performance considerations for large codebases, techniques for parallel test execution, troubleshooting strategies, and extensibility options round out the coverage, leaving readers prepared for current enterprise needs and future evolutions in .NET mocking.