我是Angular的新手,并创建待办事宜应用程序。我试图在很多地方找到解决方案,即使是我正在测试组件的情况下也是如此。这从MongoDB中获取数据,但我嘲笑了这些数据。
如何在Angular 2中测试* ngFor?
以下是模板的HTML(使用自举):
<li class="list-group-item" *ngFor="let task of tasks">
<div class=" task-date">{{task.date}}</div>
</li>
的下面是组件代码(我只增加子部分):
export class ShowTaskComponent extends OnInit{
tasks:Task[];
ngOnInit() {
setInterval(() => {this.refreshTasks()}, 3000);
}
constructor(private appService: AppService, private _router:Router){
super();
this.refreshTasks();
}
refreshTasks = function() {
this.appService.retrieveDataFromServer().subscribe((data: any) => {
//this.appService.taskArray = data;
this.tasks = data;
});
};
}
现在我添加测试代码(.spec.ts文件的子部分)...为了说明问题,所有代码(不包括进口):
let comp: ShowTaskComponent;
let fixture: ComponentFixture<ShowTaskComponent>;
let service: AppService;
let router: Router;
let debugTaskTitle: DebugElement[];
let taskTitles: any[];
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [ShowTaskComponent],
providers: [AppService],
imports: [....]
})
.compileComponents();
}));
beforeEach(() => {
fixture = TestBed.createComponent(ShowTaskComponent);
service = fixture.debugElement.injector.get(AppService);
router = fixture.debugElement.injector.get(Router);
let dummyTasks: any[] = [
{
"date": "12 October 2017",
"title": "Demo task 1",
"description": "Demo task 1 desc",
"priority" : "High",
"_id" : "1"
},
{
"date": "1 January 2018",
"title": "Demo task 2",
"description": "Demo task 2 desc",
"priority" : "Low",
"_id" : "2"
}
];
spyOn(service, 'retrieveDataFromServer').and.returnValue(Observable.of<any[]>(dummyTasks));
fixture = TestBed.createComponent(ShowTaskComponent);
comp = fixture.componentInstance;
console.log("----------------------------> comp ", comp);
debugTaskTitle = fixture.debugElement.queryAll(By.css('div.task-title'));
console.log("----------------------------> debugTaskTitle ", debugTaskTitle);
let counter: number = 0;
for(let title of debugTaskTitle) {
taskTitles.push(title.nativeElement);
taskTitles[counter].innerText = dummyTasks[counter].title;
counter ++;
}
});
//This test fails because taskTitles is undefined!
it('test whether a correct test has loaded',() =>{
expect(taskTitles).toBe(["Demo task 1", "Demo task 2"]);
});
问题出现在debugTaskTitle。这是空阵列,当我尝试使用fixture.debugElement.queryAll(By.css())
进行初始化时。
我试图在控制台上打印它(看长-------->箭头),它是空阵列。
组件comp的对象被创建并且表现很好。
有人可以建议我哪里错了吗?我迟到了三天提交这项任务。任何帮助都会很棒。
整个代码为github repo
另外,我没有看到任何浏览器时,我只运行一次考验。它应该在浏览器上显示任务!
那么这是否意味着* ngFor不会填充页面上的内容一旦.compileComponents();
被调用来在第一个beforeEach()
内生成CSS和HTML?
import {By} from @ angular/platform-browser'; –