Testing Services
Explore how to effectively test Angular services by writing unit tests for synchronous and asynchronous operations. Understand how to mock dependencies like HTTP requests using Angular's testing utilities, enabling you to validate service methods without making real HTTP calls. Gain practical knowledge of testing strategies to ensure reliable and maintainable Angular services.
We'll cover the following...
As we learned, a service can inject other services. Testing a standalone service is pretty straightforward: we get an instance from the injector and then start to query its public properties and methods.
Note: We are only interested in testing the public API of a service, which is the interface that components and other artifacts use. Private symbols do not have any value in being tested because they represent the internal implementation of the service.
There are three different types of testing that we can perform in a service:
Testing a synchronous operation, such as a method that returns a simple array.
Testing an asynchronous operation, such as a method that returns an observable.
Testing services with dependencies, such as a method that makes HTTP requests. ...