如何在单元测试中注入Input（）？

Question

所以我尝试对组件进行一些单元测试。但是我对Input（）参数有一些问题。然后特别是组件中的一个组件

所以我有这个组件：

export class EcheqDisplayComponent implements OnInit {
  echeq: EcheqSubmissionApi;


  constructor(
    private route: ActivatedRoute
  ) {
    this.echeq = this.route.snapshot.data['submission'];
  }

  ngOnInit() {
  }

  getAnswers(page: EcheqPageApi): any[] {
    return page.elements.map(element => this.echeq.answers[element.name]);
  }
}

和模板：

<div class="echeq-display" *ngIf="echeq">
  <header class="echeq-display-header header">
    <div class="echeq-display-info">
      <h1 class="heading echeq-display-heading">
        {{ echeq.definition.title }}
      </h1>
      <div class="sub-heading echeq-display-subheading">
        <span class="echeq-display-creator">
          Toegekend door:
          {{ echeq.assignedByProfName ? echeq.assignedByProfName : 'Het Systeem' }}
        </span>
        <span class="echeq-display-date">{{
          echeq.definition.createdOnUtc | date: 'dd MMM'
        }}</span>
      </div>
    </div>
    <app-meta-box
      [metadata]="{
        numPages: echeq.definition.numPages,
        vPoints: echeq.definition.awardedVPoints
      }"
    ></app-meta-box>
  </header>
  <main class="echeq-display-questions body">
    <app-echeq-question
      *ngFor="let page of echeq.definition.pages; let i = index"
      [page]="page"
      [readonly]="true"
      [number]="i + 1"
      [answers]="getAnswers(page)"
    ></app-echeq-question>
  </main>
</div>

和单元测试：

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { EcheqDisplayComponent } from './echeq-display.component';
import { ParticipantEcheqModule } from '../../participant-echeq.module';
import { RouterModule, ActivatedRoute } from '@angular/router';
import { MockActivatedRoute } from 'src/app/shared/mocks/MockActivatedRoute';
import { MetaData } from '../meta-box/meta-box.component';

describe('EcheqDisplayComponent', () => {
  let component: EcheqDisplayComponent;
  let fixture: ComponentFixture<EcheqDisplayComponent>;
  const metaData: MetaData = new MetaData();
  // const metaDataInfo = fixture.debugElement.componentInstance;


  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [ ],
      providers: [
        { provide: ActivatedRoute, useClass: MockActivatedRoute }
      ],
      imports:[
        ParticipantEcheqModule

      ]
    })
    .compileComponents();
  }));

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

  fit('should create component', () => {
    metaData.numPages = 20;
    expect(component).toBeTruthy();
  });
});

但它仍然说：

TypeError：无法读取未定义的属性'numPages'。

所以我必须更改它是否起作用？

谢谢

因此，元数据来自app-meta-box组件。它看起来像这样：

export class MetaData {
  numPages: number;
  vPoints: number;
}

@Component({
  selector: 'app-meta-box',
  templateUrl: './meta-box.component.html',
  styleUrls: ['./meta-box.component.scss']
})
export class MetaBoxComponent implements OnInit {
  @Input() metadata: MetaData;

  constructor() {}

  ngOnInit() {}

}

Answer 1

回答您的问题：

component.metadata = /// whatever you want this to be

Answer 2

您在使用numPages: echeq.definition.numPages时出错。高兴的是，echeq也未定义。

您可以尝试：

component.echeq = {
   definition: {
     numPages: 9
   }
}

或者更好的方法是从this.route.snapshot.data['submission'];返回此值，因此从MockActivatedRoute返回>