What you'll learn

Every API change risks breaking something — a route that no longer resolves, a validation rule that silently disappears, an authorization policy that stops working. Manual testing can't keep up, and poorly written automated tests can be worse than no tests at all: they're slow, brittle, and give false confidence. In this course, Testing ASP.NET Core 10 Web APIs, you'll gain the ability to write automated tests that validate the real behavior of your APIs — from business logic to HTTP contracts. First, you'll explore unit testing business rules, services, and controller actions using xUnit and Moq; learning when mocks add value and when real dependencies give you more confidence. Next, you'll discover integration testing with WebApplicationFactory, sending real HTTP requests through the full middleware pipeline to test routing, validation, serialization, and error responses — for both controller-based and Minimal API endpoints. Finally, you'll learn how to test authentication and authorization without a real identity provider, verify middleware and filter behavior, manage test database state, and replace external HTTP dependencies. When you're finished with this course, you'll have the skills and knowledge of ASP.NET Core testing needed to build a test suite that protects your API as it evolves — catching real bugs without slowing you down.