无法在使用Jasmine和Angular的单元测试中获取选择按钮点击

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { MyComponent } from './my-component.component';

describe('MyComponent', () => {
  let component: MyComponent;
  let fixture: ComponentFixture<MyComponent>;

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      declarations: [ MyComponent ]
    })
    .compileComponents();
  });

  beforeEach(() => {
    fixture = TestBed.createComponent(MyComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should trigger change event on select button click', () => {
    // 获取选择按钮的引用
    const selectButton = fixture.nativeElement.querySelector('select');

    // 模拟点击事件
    selectButton.dispatchEvent(new Event('change'));

    // 断言或执行其他操作来验证结果
    expect(component.someProperty).toBe(expectedValue);
  });
});