ngAfterViewInit(): void {
  this.offsetPopoverPosition();
}

it('ngAfterViewInit() method should call offsetPopoverPosition() method', () => {
    const mockListener = jest.spyOn(cmp, 'offsetPopoverPosition');
    const spy = mockListener.mockImplementation(() => {
      console.log('in the mock');
    });

    cmp.ngAfterViewInit();
    expect(spy).toHaveBeenCalled();
  });