Testing Angular interceptors with Spectator

interceptors.spec.ts

import { HttpErrorResponse, HttpRequest, HttpResponse } from '@angular/common/http';
import { Router } from '@angular/router';
import { createService, createSpyObject } from '@netbasal/spectator';
import { of, throwError } from 'rxjs';
import { RedirectInterceptor } from './redirect-interceptor.service';
import anything = jasmine.anything;

describe('RedirectInterceptorService', () => {
  const spectator = createService({
    service: RedirectInterceptor,
    mocks: [Router]
  });

  const dummyRequest = createSpyObject(HttpRequest);

  const interceptWithError = (error: Error) => {
    spectator.service.intercept(dummyRequest, {
      handle: () => throwError(error)
    }).subscribe(
      () => fail('Should fail'),
      e => expect(e).toBe(error)
    );
  };

  const interceptWithResponse = (response: HttpResponse<any>) => {
    spectator.service.intercept(dummyRequest, {
      handle: () => of(response)
    }).subscribe();
  };
    
  it('should redirect when unauthorized or forbidden', () => {
    [401, 403].forEach(status => {
      interceptWithError(new HttpErrorResponse({ status }));
      expect(spectator.get<Router>(Router).navigate).toHaveBeenCalledWith(['unauthorized'], anything());
    });
  });
    
  it('should not redirect for other HTTP errors', () => {
    [500].forEach(status => {
      interceptWithError(new HttpErrorResponse({ status }));
      expect(spectator.get<Router>(Router).navigate).not.toHaveBeenCalled();
    });
  });
    
  it('should not redirect when OK', () => {
    [200].forEach(status => {
      interceptWithResponse(new HttpResponse<any>({ status }));
      expect(spectator.get<Router>(Router).navigate).not.toHaveBeenCalled();
    });
  });
    
  it('should not redirect for other error', () => {
    interceptWithError(new Error('some error'));
    expect(spectator.get<Router>(Router).navigate).not.toHaveBeenCalled();
  });
});