这是我的解决方案--特别是返回一个200的对象的部分，它足以模拟对api-service的调用，该调用返回Angular的httpService.delete的结果。

describe('ItemStoreService', () => {
      let service: ItemStoreService;
      let itemApiServiceSpy: SpyObj<ItemApiService>;
      let notifyServiceSpy: SpyObj<NotifyService>;
      let anItem: Item;
    
      beforeEach(() => {
        anItem = {
          id: 1,
          name: 'testName',
        };
    
        itemApiServiceSpy = createSpyObj('ItemApiService', ['delete', 'loadActiveItems']);
        notifyServiceSpy = createSpyObj('NotifyService', ['notifyError', 'notifySuccess']);
    
        TestBed.configureTestingModule({
          providers: [
            { provide: ItemApiService, useValue: itemApiServiceSpy },
            { provide: NotifyService, useValue: notifyServiceSpy },
          ],
        }).compileComponents();
        service = TestBed.inject(ItemStoreService);
      });
    
      it('should be created', () => {
        expect(service).toBeTruthy();
      });
    
      it('delete should call notifyError on error ', () => {
        itemApiServiceSpy.delete.and.returnValue(
          throwError(() => {
            return { status: 500, message: 'testError' };
          })
        );
    
        service.delete(anItem.id);
    
        expect(itemApiServiceSpy.delete).toHaveBeenCalledOnceWith(anItem.id);
        expect(notifyServiceSpy.notifySuccess).not.toHaveBeenCalled();
        expect(notifyServiceSpy.notifyError).toHaveBeenCalledWith(
          'A problem was encountered while deleting Non-Production Bottle Lot ' + anItem.id
        );
      });
    
      it('delete should call notifySuccess on success ', () => {
        let loadActiveItemsSpy = spyOn(service, 'loadActiveItems');
    
        itemApiServiceSpy.delete.and.returnValue(of({ status: 200, message: 'deleted.' }));
    
        service.delete(anItem.id);
    
        expect(itemApiServiceSpy.delete).toHaveBeenCalledOnceWith(anItem.id);
        expect(notifyServiceSpy.notifyError).not.toHaveBeenCalled();
        expect(loadActiveItemsSpy).toHaveBeenCalled();
        expect(notifyServiceSpy.notifySuccess).toHaveBeenCalledWith('Non-Production Bottle Lot was deleted.');
      });
    });