Monitoring and controlling dependency calls using method stubs and spies

One crucial aspect of testing in Angular applications is the ability to monitor and control dependency calls. Dependencies are external resources or services that a piece of code relies on to function correctly. Monitoring and controlling these dependency calls allows developers to ensure that their code interacts correctly with external systems and handles different scenarios gracefully.

Spies and method stubs are two powerful techniques within Angular’s testing framework that enable developers to achieve this level of control. Spies allow developers to monitor function calls, record information about those calls, and assert expectations about their usage. On the other hand, method stubs provide a way to replace real dependencies with simplified versions, allowing developers to control the behavior of those dependencies during testing.

By using spies, developers can verify that the correct functions...