如何在plotly.js中手动触发事件并进行单元测试

Question

我要对该代码进行单元测试

Plotly.newPlot(this.plotViewPort.nativeElement, this.data, this.layout);

this.plotViewPort.nativeElement.on('plotly_relayout', (eventdata) => {
   this.onUserZoom(eventdata);
});

如何触发 tests文件

中的plotly_relayout事件

到目前为止我的尝试

 it('should plotly_relayout event to work as expected', () => {
    component.droped({ dropData: STORES[0]});
    fixture.detectChanges();

    const elem = component.plotViewPort
    var event = new CustomEvent('plotly_relayout', { test: true });
    elem.nativeElement.dispatchEvent(event);
    console.log(component.plotViewPort.nativeElement);
    expect(component.onUserZoom).toHaveBeenCalled();
  });