如何使用Angular 8单元测试检查图像是否存在于给定路径中？

npm install @angular-devkit/build-angular
npm install jasmine-core karma karma-chrome-launcher karma-cli karma-jasmine karma-jasmine-html-reporter

import { TestBed, async, ComponentFixture } from '@angular/core/testing';
import { ImageComponent } from './image.component';

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

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

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

  it('should check if image exists at given path', () => {
    const imagePath = 'path/to/image.jpg';
    const imageElement = fixture.nativeElement.querySelector('img');
    component.checkImageExists(imagePath);
    fixture.detectChanges();
    expect(imageElement.src).toContain(imagePath);
  });
});

ng test