无法在Angular 2单元测试(Jasmine)中模拟按键事件

Question

我正在使用一个指令来获取用作过滤器文本的输入数据.

这是我在指令中的hostlistener:

@HostListener('input', ['$event.target.value'])
  public onChangeFilter(event: any): void {
    console.log('input event fired, value: ' + event);
    this.columnFiltering.filterString = event;
    this.filterChanged.emit({filtering: this.columnFiltering});
  }

这段代码工作正常,我无法进行单元测试.

我订阅了filterChanged EventEmitter,在我的单元测试中检查了值.

我尝试模拟按键事件来更改值并尝试设置值属性.这些都不适合我.

这是我的spec文件:

describe('Table View', () => {
  let fixture: ComponentFixture<any>;
    let context: TableComponent;
   beforeEach(() => {
     TestBed.configureTestingModule({
          providers: [
            TableComponent,
          ],
          imports: [TableModule],
      });
      fixture = TestBed.createComponent(TableComponent);
      context = fixture.componentInstance;
    });
it('should allow filter', () => {
      const element = fixture.nativeElement;
      context.config = config;
      fixture.detectChanges();

      let tableChangeCount = 0;
      let tableEvent: any;
      context.tableChanged.subscribe((event: any) => {
        tableChangeCount++;
        tableEvent = event;
      });
      // Check if table exists
      let inputElement = element.querySelectorAll('tr')[1].querySelector('input');
    let e = new KeyboardEvent("keypress", {
            key: "a",
            bubbles: true,
            cancelable: true,
          });
          inputElement.dispatchEvent(e);
 });

});

我试过设定价值:

let attrs = inputElement.attributes;
      inputElement.setAttribute('value', 'abc');
       for (let i = attrs.length - 1; i >= 0; i--) {
         // Attribute value is set correctly
         if (attrs[i].name === 'value') {
         console.log(attrs[i].name + "->" + attrs[i].value);
         }
       }

任何人都可以帮助我,我怎样才能对它进行单元测试？

Answer 1

我在单元测试中模拟按键时遇到了一些麻烦.但是Seyed Jalal Hosseini发现了一个答案.这可能就是你所追求的.

如果您正在尝试模拟按键,则可以通过调用dispatchEvent(new Event('keypress'));元素来触发事件.

以下是我所指的答案,其中提供了更多详细信息:https://stackoverflow.com/a/37956877/4081730

如果要设置按下的键,也可以这样做.

const event = new KeyboardEvent("keypress",{
    "key": "Enter"
});
el.dispatchEvent(event);

我刚刚遇到的更多信息:https://developer.mozilla.org/en-US/docs/Web/Guide/Events/Creating_and_triggering_events

Answer 2

如果您想使用密钥代码（或“哪个”），您可以这样做：

// @HostListener('document:keypress')

const escapeEvent: any = document.createEvent('CustomEvent');
escapeEvent.which = 27;
escapeEvent.initEvent('keypress', true, true);
document.dispatchEvent(escapeEvent);