如何在angular中对剪贴板副本进行单元测试？

import { ClipboardComponent } from './clipboard.component';
import { ClipboardService } from './clipboard.service';
import { TestBed, ComponentFixture } from '@angular/core/testing';

describe('ClipboardComponent', () => {
  let component: ClipboardComponent;
  let fixture: ComponentFixture<ClipboardComponent>;
  let clipboardService: ClipboardService;

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

  beforeEach(() => {
    fixture = TestBed.createComponent(ClipboardComponent);
    component = fixture.componentInstance;
    clipboardService = TestBed.inject(ClipboardService);
    fixture.detectChanges();
  });

  // 测试用例将在这里编写
});

it('should copy text to clipboard', () => {
  const text = 'Hello, world!';
  spyOn(clipboardService, 'copyToClipboard');
  component.copyText(text);
  expect(clipboardService.copyToClipboard).toHaveBeenCalledWith(text);
});