Controllers in Spring MVC are considered testable artifacts primarily because they can be easily tested in isolation from other components of the application. This testability is facilitated by several features and tools provided by the Spring Framework:
Separation of Concerns: Spring MVC follows the Model-View-Controller (MVC) design pattern, which separates the controller logic from the business logic and the view layer. This separation allows developers to test the controllers independently of the user interface and the underlying business logic[1][2][3][6].
Dependency Injection: Spring's dependency injection mechanism allows for easier configuration and mock implementation of dependencies used by controllers. This means that controllers can be tested without the need to set up their dependencies, such as services or databases. Instead, mock objects can be injected to simulate the behavior of these dependencies during testing[1][2][3].
MockMVC: Spring provides the MockMVC class, which is a powerful tool for testing controllers by simulating HTTP requests and asserting the responses. MockMVC allows developers to perform and test different types of HTTP requests (GET, POST, etc.) and validate the responses without actually starting a web server[1][3][5].
