组件方法 angular 7 的单元测试

Question

我的组件代码 -

import { Component, EventEmitter, Input, OnInit, OnChanges, SimpleChanges,  Output } from '@angular/core';
import { CI, CiWithStatus } from '../ci-list.service';
import { ContextPanelApi } from '../../../../../../../../shared/shared-html/js/directives/oprContextPanel/oprContextPanel/oprContextPanelApi.service';

@Component({
  selector: 'opr-watchlist-cards',
  templateUrl: './watchlist-cards.component.html',
  styleUrls: ['./watchlist-cards.component.scss']
})
export class WatchlistCardsComponent implements OnInit, OnChanges {

  @Input() ciList: CiWithStatus[];
  @Input() itemWidth: number;
  @Input() itemHeight: number;
  @Input() zoomLevel: number;

  @Output() onSelectedCisChanged: EventEmitter<CI[]> = new EventEmitter<CI[]>();

  private _selectedItems: CI[] = [];

  constructor(private _oprContextPanelApiService: ContextPanelApi) {
  }

  ngOnInit() {
    console.debug('ciList', this.ciList);
  }

  ngOnChanges(changes: SimpleChanges): void {
    if(changes.zoomLevel) {
      this.zoomLevel = changes.zoomLevel.currentValue;
    }
  }

  onItemClick(event: MouseEvent, ci: CI) {
    if (event.ctrlKey) {
      if (this.isSelected(ci)) {
        this._selectedItems.splice(this._selectedItems.indexOf(ci), 1);
      } else {
        this._selectedItems.push(ci);
      }
    } else {
      this._selectedItems = [ci];
    }
    this.onSelectedCisChanged.emit(this._selectedItems);
  }

  onItemRightClick(event: MouseEvent, ci: CI) {
    const position = {left: event.clientX, top: event.clientY};
    const contextPanelConfig = {
      title: 'context menu dummy ' + ci.name,
      position
    };
    const contextPanelPages = [];
    this._oprContextPanelApiService.openContext(contextPanelConfig, contextPanelPages, () => {
    });
    return false; //prevent native browser context menu
  }

  isSelected(ci: CI) {
    return this._selectedItems.includes(ci);
  }
}

我的规范文件代码 -

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { SimpleChange } from '@angular/core';
import { WatchlistCardsComponent } from './watchlist-cards.component';
import { AppSharedModule } from '../../../../../app-shared/src/lib/app-shared.module';
import { WatchlistCardComponent } from './watchlist-card/watchlist-card.component';
import { ContextPanelApi } from 'shared/directives/oprContextPanel/oprContextPanel/oprContextPanelApi.service';

export class MockContextPanelApi {

}

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

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [AppSharedModule],
      declarations: [WatchlistCardComponent, WatchlistCardsComponent],
      providers: [{ provide: ContextPanelApi, useClass: MockContextPanelApi }]
    })
      .compileComponents();
  }));

  beforeEach(() => {
    fixture = TestBed.createComponent(WatchlistCardsComponent);
    component = fixture.componentInstance;
    params = {
      ci: {
        global_id: "9e76bafea39c49e786360baeb2551fd7",
        icon: "/odb/icons/unix/unix_32.svg",
        id: "9e76bafea39c49e786360baeb2551fd7",
        last_changed: 1540465938749,
        long_id: "1;;9e76bafea39c49e786360baeb2551fd7",
        name: "srv0",
        status: 0,
        type: "unix",
        type_label: "Unix",
        event: "link"
      },
      event: {

      }
    };
    fixture.detectChanges();
  });

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

  it('should call ngOnChanges', () => {
    component.zoomLevel = 3;
    component.ngOnChanges({
      zoomLevel: new SimpleChange(null, component.zoomLevel, true)
    });
    fixture.detectChanges();
  })

  it('should call the onItemClick method', async(() => {
    spyOn(component, 'onItemClick');
    component.onItemClick(params.event, params.ci);
    fixture.whenStable().then(() => {
      expect(component.onItemClick).toHaveBeenCalled();
    });
  }));

  it('should call the onItemRightClick method', async(() => {
    spyOn(component, 'onItemRightClick');
    component.onItemRightClick(params.event, params.ci);
    expect(component.onItemRightClick).toHaveBeenCalled();
  }));

  it('should call the isSelected method', async(() => {
    spyOn(component, 'isSelected');
    component.isSelected(params.ci);
    expect(component.isSelected).toHaveBeenCalled();
  }));

});

我想涵盖这些功能，我尝试在规范中这样做，但它仍然说功能未涵盖。

请指导我如何涵盖 isSelected、onItemRightClick、onItemClick 方法的函数和语句

谢谢。

Answer 1

原因是spyOn()，它将用存根替换原始方法。在Jasmine Doc 中阅读有关间谍的内容。所以，当你调用component.onItemClick. 你只是在调用间谍而不是原始函数。因此没有代码覆盖。

修复： spyOn(component, 'onItemClick').and.callThrough();。这在文档中也有解释。

但是，IMO 您正在编写的测试并不是很有用。例如：

 line 1:     component.onItemClick(params.event, params.ci);
             fixture.whenStable().then(() => {   
 line 2:    expect(component.onItemClick).toHaveBeenCalled();  

line 1- 您正在手动调用onRightClick(). 因为您手动调用该函数， line 2将始终为真。但是，IRL 此功能将在 HTML 中右键单击/单击元素时触发。

您应该做的是获取组件参考（我没有测试过这段代码，它只是一个参考，我假设您有一个元素（按钮），其中有一个onclick）：

let fixture: ComponentFixture<WatchlistCardsComponent>;    
const buttonEle: HTMLElement = fixture.nativeElement.querySelector('button');
spyOn(component, 'onItemClick');
button.click();
fixture.whenStable().then(() => {   
   expect(component.onItemClick).toHaveBeenCalled(); ...

这将在组件函数上创建一个间谍（与您所做的相同），不同之处在于您不是onItemClick手动调用，而是按钮单击会自动触发函数调用，因此无需手动调用 eventHandler。