我有一个使用EventEmitter的组件,当单击页面上的某个人时使用EventEmitter.有什么办法可以在单元测试期间观察EventEmitter,并使用TestComponentBuilder单击触发EventEmitter.next()方法的元素,并查看发送的内容？
您的测试可能是：
it('should emit on click',inject([],() => {
tcb.createAsync(MyComponent)
.then((fixture) => {
// spy on event emitter
let component = fixture.componentInstance;
spyOn(component.myEventEmitter,'emit');
// trigger the click
let nativeElement = fixture.nativeElement;
let button = nativeElement.querySelector('button');
button.dispatchEvent(new Event('click'));
fixture.detectChanges();
expect(component.myEventEmitter.emit).toHaveBeenCalledWith('hello');
});
}));
当你的组件是：
@Component({ ... })
class MyComponent {
@Output myEventEmitter = new EventEmitter();
buttonClick() {
this.myEventEmitter.emit('hello');
}
}