it('should call the method callWorkBookAPI', () => {
  const mockData = new Blob(['test'], { type: 'application/octet-stream' });

  const service = fixture.debugElement.injector.get(DataManagementService);

  spyOn(service, 'getWorkbook').and.returnValue({
    subscribe: (callback: any) => {
      callback(mockData);
      return { unsubscribe: jasmine.createSpy('unsubscribe') };
    }
  });

  spyOn(document, 'createElement').and.returnValue({
    click: jasmine.createSpy('click')
  } as any);

  spyOn(window.URL, 'createObjectURL').and.returnValue('blob:mock-url');

  component.callWorkBookAPI();

  expect(service.getWorkbook).toHaveBeenCalled();
});