How can I test Angular interceptors effectively?

How can I test Angular interceptors effectively?

To test Angular interceptors, you can use Jasmine and TestBed to create unit tests that mock HTTP requests.

Can you provide a code example for that?

Sure! Here's a simple example:

import { TestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { MyInterceptor } from './my-interceptor';

describe('MyInterceptor', () => {
  let httpMock: HttpTestingController;

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [HttpClientTestingModule],
      providers: [MyInterceptor]
    });
    httpMock = TestBed.inject(HttpTestingController);
  });

  it('should intercept requests', () => {
    // Your test logic here
  });
});

What should I test for in the interceptor?

You should test for request modifications, response handling, and error handling to ensure the interceptor behaves as expected.

Are there any best practices for writing these tests?

Yes, keep your tests isolated, use spies to mock dependencies, and ensure you clean up after each test to avoid side effects.