如何在表素数Ng中创建virtualScroll的单元测试

Question

我无法在表中使用lazayload测试virtualScroll

  <p-table class="basicTable" [value]="cars" [scrollable]="true" [rows]="100" scrollHeight="500px"
             (onLazyLoad)="load($event)" [rows]="100" lazy="true"
             [virtualScroll]="true">

  const tableEl = fixture.debugElement.query(By.css('.p-datatable-virtual-scrollable-body'));
    fixture.detectChanges();
    const bodyRows = tableEl.query(By.css('.p-datatable-tbody')).queryAll(By.css('tr'));
    console.log(bodyRows)

bodyRows为空

谢谢

Answer 1

Angular团队的单元测试为我提供了一个答案。在CDK Virtual Scroll显示数据之前，有许多异步步骤，所以我们必须模拟这些步骤。将以下函数添加到.spec.ts文件的顶部，并在将fixture作为参数传递时调用它，而不是fixture.detectChanges()：

const finishInit = (fixture: ComponentFixture<any>) => {
  // On the first cycle we render and measure the viewport.
  fixture.detectChanges();
  flush();

  // On the second cycle we render the items.
  fixture.detectChanges();
  flush();

  // Flush the initial fake scroll event.
  tick(500);
  flush();
  fixture.detectChanges();
};

您的it还需要使用fakeAsync

it('should display virtual scroll data', fakeAsync(() => {


}));