Testing a REST server from Angular without mocking

I know that I should test a REST server from Angular with a mock, and there are dozens of examples on the web how to do this. But assume I want to test a service on the real thing which I have full control over.

Here is the working mocked version:

describe('SgformsService', () => {
  let sgformsService: SgformsService
  let httpMock: HttpTestingController

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

    it('should return a single item when mocked', () => {
    sgformsService.getSingle().subscribe(
      (sg: SgFormsBase) => {
        expect(sg.id).toEqual(34)
        expect(sg.pat_no).toEqual(1704)
      })
      const req = httpMock.expectOne(
        'http://localhost:8000/getsingle/Endoskopie/1631/2019-03-19/arzt/0', 'call to api');
      expect(req.request.method).toBe('GET');
      req.flush({
        id: 34,
        pat_no: 1704
      })
   });
});

How do I redirect this to use the REST server instead of the mock? The code below does not work because I don't know how to create HttpClient for SgformsService.

describe('SgformsService without Mocking', () => {
  let sgformsService: SgformsService
  //let httpClient: HttpClient

  beforeEach(function() {
  //  httpClient = new HttpClient()
  //  sgformsService = new SgformsService(httpClient);
  });

  // https://angular.io/guide/testing#service-tests
  it('should return a single item from server',
    (done: DoneFn) => {
      sgformsService.getSingle().subscribe(
      (sg: SgFormsBase) => {
        expect(sg.id).toEqual(34)
        expect(sg.pat_no).toEqual(1704)
        done()
      });
    });

});