Question

我正在学习angular以及如何在Angular中编写测试。我遇到错误“无法读取未定义的属性'subscribe'”时，需要一些有关如何模拟BehaviorSubject的指导。

This is the code for my service:
@Injectable({
  providedIn: 'root'
})
export class NumberService {
  public number = new BehaviorSubject<string>(undefined);
  private lastNumber = undefined;
  constructor() { }

  next (number: string) {
    if (number !== this.number) { 
      this.number.next(number);
      this.lastNumber = number; 
    }
  }
}

然后我在组件中订阅了该号码：

现在是我的测试文件

  const restStub = jasmine.createSpyObj('RestService', ['getDetails']);
  const NumberStub = jasmine.createSpyObj('NumberService', ['next']);

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [ MyComponent ],
      imports: [
        TranslateModule.forRoot(),
      ],
      providers: [
        { provide: RestService, useValue: restStub },
        { provide: NumberService, useValue: NumberStub},
      ]
    })
    .compileComponents();
  }));

it('should display ......', () => {
  numberStub.next('abc');
  restStub.getDeviceInfo.and.returnValue(of(SampleData()));
  createComponent();
  expect(component.deviceDetails.type).toBe('abc');
});

任何人都可以提供有关如何正确模拟BehaviorSubject的帮助吗？预先感谢！

Answer 1

根据您的实现，我创建了一个类似的测试。对于服务，您只需创建它们的实例并使用它们即可。

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无法读取未定义的属性“ next”-如何模拟BehaviorSubject

1 个答案: