javascript - Angular2 + karma 测试 : “Illegal state: Could not load the summary for directive Foo.”

Question

我有一个看起来像这样的组件:

import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'app-youtube',
  templateUrl: './youtube.component.html',
  styleUrls: ['./youtube.component.css']
})
export class YoutubeComponent implements OnInit {

  constructor() { }

  ngOnInit() {
  } 

}

在我的 karma 规范中，我有以下内容:

import { async, ComponentFixture, TestBed } from '@angular/core/testing';

import { YoutubeComponent } from './youtube.component';

describe('YoutubeComponent', () => {
  let component: YoutubeComponent;
  let fixture: ComponentFixture<YoutubeComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      // providers: [YoutubeComponent],tried this, and it makes no difference
      declarations: [ YoutubeComponent ]
    })
    .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(YoutubeComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });
});

我在 Karma 浏览器中遇到的错误如下所示:

Error: Illegal state: Could not load the summary for directive YouTubeComponent.

似乎previous, related questions通过添加行 declarations: [ YoutubeComponent ] 来解决，我已经有了。还有其他建议吗？

github 上有一个可重现的例子:

git clone https://github.com/Atticus29/dataJitsu.git
cd dataJitsu
git checkout modalSO
rm package-lock.json
npm install
npm test

Answer 1

@Atticus29 通常在您错过以下操作时会出现此错误:

1. 声明一些相关组件
2. 在导入中添加一些引用的模块

尝试检查任何引用的组件或模块。