Unable to catch HttpResponseError mocked on Jasmine

Question

I am just testing that a component will show an error alert when a call to a service is returning a 404 error.

The component method:

getChannels() {
this.channelService.getActiveChannels()
  .subscribe(
    (result) => {
      // whatever.
    },
    (error) => {
      this.alertService.showError('Error', 'No Connection');
      console.log(error);
    }
  );

The service method

  getActiveChannels() {

return this.http.get<any>(api.apiDomain + 'channels')
  .pipe(map((response) => response));

Ands the test spec :

it('error alert called when get channels thrown an error', () => {

const as = fixture.debugElement.injector.get(AlertService);
const error = new HttpErrorResponse({error: 'foo', status: 0});
const cs = fixture.debugElement.injector.get(ChannelService);
jasmine.getEnv().allowRespy(true);

cs.getActiveChannels = jasmine.createSpy('getActiveChannels').and.returnValue(of(error));

component.getChannels();
expect(as.showError).toHaveBeenCalledWith('Error', 'No Connection');

});

This approach, overriding the existing spy, works as a charm, when returning any array value. But when I return this error, if I debug I see that the subscriber handles that error as a proper result, not as an error, so it never triggers the alert.

I'd like to keep my test as simple as possible without using HttpClientTestingModule that I think is overkilling for that simple task.

SOLUTION:

    cs.getActiveChannels = jasmine.createSpy('getActiveChannels').and.returnValue(throwError({status: 404}));