我们如何访问ng-select的输入以进行单元测试？

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { NgSelectComponent } from '@ng-select/ng-select';

let fixture: ComponentFixture<MyComponent>;
let ngSelectComponent: NgSelectComponent;

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

  fixture = TestBed.createComponent(MyComponent);
  ngSelectComponent = fixture.componentInstance.ngSelect;
});

it('should set input value', () => {
  ngSelectComponent.items = ['Option 1', 'Option 2', 'Option 3'];
  ngSelectComponent.writeValue('Option 2');
  fixture.detectChanges();

  expect(ngSelectComponent.selectedItems).toEqual(['Option 2']);
});

it('should handle user input', () => {
  const inputElement = fixture.nativeElement.querySelector('.ng-select .ng-select-container input');
  inputElement.value = 'Option 3';
  inputElement.dispatchEvent(new Event('input'));
  fixture.detectChanges();

  expect(ngSelectComponent.selectedItems).toEqual(['Option 3']);
});

it('should handle input changes', () => {
  ngSelectComponent.items = ['Option 1', 'Option 2', 'Option 3'];
  fixture.detectChanges();

  ngSelectComponent.items = ['Option 4', 'Option 5'];
  fixture.detectChanges();

  expect(ngSelectComponent.items).toEqual(['Option 4', 'Option 5']);
});