How can I mock HTTP requests in Angular?

How can I mock HTTP requests in Angular?

You can use the HttpClientTestingModule to mock HTTP requests in Angular. Would you like a code example?

Yes, please provide a code example.

Sure! Here’s a simple example:

import { TestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { MyService } from './my.service';

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

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

  it('should fetch data', () => {
    service.getData().subscribe(data => {
      expect(data).toEqual(mockData);
    });

    const req = httpMock.expectOne('api/data');
    expect(req.request.method).toBe('GET');
    req.flush(mockData);
  });

  afterEach(() => {
    httpMock.verify();
  });
});

This code sets up a test for a service that makes an HTTP GET request.

What is the purpose of the HttpTestingController?

The HttpTestingController allows you to mock and control HTTP requests in your tests, making it easier to test your services without making real HTTP calls.