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我对 Angular Material 单元测试和服务单元测试都比较陌生。我为我的应用程序创建了一个服务，我可以使用它调用 Material SnackBar 打开函数并传递一个消息参数。它在需要时在每个组件中都可以正常工作，但是对它的单元测试对我来说很糟糕。

import { Injectable } from '@angular/core';
import { MatSnackBar, MatSnackBarRef, MatSnackBarConfig } from '@angular/material/snack-bar';

@Injectable({
  providedIn: 'root',
})
export class NotificationService {
  private snackBarConfig: MatSnackBarConfig;
  private snackBarRef: MatSnackBarRef<any>;
  private snackBarAutoHide = '5000';

  constructor(private sb: MatSnackBar) {}

  openSnackBar(message) {
    this.snackBarConfig = new MatSnackBarConfig();
    this.snackBarConfig.duration = parseInt(this.snackBarAutoHide, 0);
    this.sb.open(message, 'Dismiss', this.snackBarConfig);
  }
}

而所谓的测试规范文件是这样的：

import { Overlay } from '@angular/cdk/overlay';
import { TestBed } from '@angular/core/testing';
import { MatSnackBar } from '@angular/material/snack-bar';
import { createServiceFactory, SpectatorService } from '@ngneat/spectator';
import { NotificationService } from './notification-service';

describe('NotificationService testing:', () => {
  let spectator: SpectatorService<NotificationService>;
  const createService = createServiceFactory({
    service: NotificationService,
    providers: [MatSnackBar, Overlay],
    entryComponents: [],
    mocks: [NotificationService],
  });

  beforeEach(() => (spectator = createService()));

  it('should openSnackBar() be known as function', () => {
    expect(typeof spectator.service.openSnackBar).toEqual('function');
  });

  it('should be created', () => {
    const dateService = spectator.inject(NotificationService);
    spyOn(spectator.service, 'openSnackBar');
    dateService.openSnackBar('Test');
    expect(spectator.service.openSnackBar).toHaveBeenCalledWith('Test');
  });
});

我的问题如下：

  1. 为什么我的业力报道说 openSnackBar(message) 方法没有经过测试？我的意思是至少我测试它是否是一个函数。
  2. 我如何才能真正独立地测试这样的服务？

先感谢您。

4

1 回答 1

2

好的，我在朋友的帮助下解决了这个问题。第一个问题是在我的构造函数中，我定义了一个私有版本，而不是 SnackBar ( private sb: MatSnackBar-> public sb: MatSnackBar) 的公共版本。其次，我稍微修改了测试文件，现在它看起来像这样并且工作正常：

import { Overlay } from '@angular/cdk/overlay';
import { TestBed } from '@angular/core/testing';
import { MatSnackBar, MatSnackBarModule, MatSnackBarConfig } from '@angular/material/snack-bar';
import { createServiceFactory, SpectatorService } from '@ngneat/spectator';
import { NotificationService } from './notification-service';

describe('NotificationService testing:', () => {
  let spectator: SpectatorService<NotificationService>;
  let snackBar: MatSnackBar;
  let snackBarConfig: MatSnackBarConfig;

  const createService = createServiceFactory({
    service: NotificationService,
    imports: [MatSnackBarModule],
    providers: [MatSnackBarModule, Overlay],
    entryComponents: [],
    mocks: [NotificationService],
  });

  beforeEach(() => {
    TestBed.configureTestingModule({});
    snackBar = TestBed.inject(MatSnackBar);
    spectator = createService();
  });

  it('should service be created', () => {
    const service: NotificationService = TestBed.inject(NotificationService);
    expect(service).toBeTruthy();
  });

  it('should openSnackBar() be known as function', () => {
    expect(typeof spectator.service.openSnackBar).toEqual('function');
  });

  it(`should openSnackBar() call SnackBar's own open()`, () => {
    const service: NotificationService = TestBed.inject(NotificationService);
    snackBarConfig = new MatSnackBarConfig();
    snackBarConfig.duration = parseInt('5000', 0);
    const serviceSpy = spyOn(service, 'openSnackBar').and.callThrough();
    const snackSpy = spyOn(snackBar, 'open');
    expect(serviceSpy).not.toHaveBeenCalled();
    expect(snackSpy).not.toHaveBeenCalled();
    service.openSnackBar('Hello');
    expect(serviceSpy).toHaveBeenCalledWith('Hello');
    expect(snackSpy).toHaveBeenCalledWith('Hello', 'Dismiss', snackBarConfig);
  });
});

希望如果有人在未来遇到同样的问题，它会有所帮助。我也确信，有一种更好、更好的方法可以做到这一点，但现在它正在发挥作用并提供 100% 的覆盖率，这很重要。但热忱欢迎日后对此提出修改建议。

于 2020-05-12T07:53:25.223 回答