角度单元测试函数。管道不是函数

Question

我知道有一个类似的问题here

但我正在按照建议的答案进行操作，但我仍然收到此错误

基本上我有这样的功能

checkForInvitation() {
        this._join.joinInformationSource.pipe(filter(x => x !== null)).subscribe(result => {
            this.joinInformation = result;
            this.setFields(result.userInfo);
        });
    }

基本上它获取信息，然后调用另一个方法来预填充一些表单字段。

现在我正在尝试测试这种方法，所以我创建了一个像这样的间谍......

// ...

const joinServiceSpy = jasmine.createSpyObj('JoinService', ['joinInformationSource']);

// ...

providers: [
    { provide: JoinService, useValue: joinServiceSpy }
]

// ...

joinService = TestBed.get(JoinService);

it('should prepopulate fields if there is join information', () => {
   let joinInfoSpy = joinService.joinInformationSource.and.returnValue(
       of(
          // ... object
       )
   )
});

现在当我运行 ng test 时，我反复收到此错误

this._join.joinInformationSource.pipe is not a function

这是我的加入服务

joinInformationSource = new BehaviorSubject<JoinInformation>(null);

setJoinInformation(joinInformation: JoinInformation) {
    this.joinInformationSource.next(joinInformation);
}

我在这里做错了什么？？

Answer 1

根据文档createSpyObj 接受方法列表作为第二个参数。因此，当您创建模拟对象时，您将 joinInformationSource 创建为一个函数。

const joinServiceSpy = jasmine.createSpyObj('JoinService', ['joinInformationSource']);

//now joinSeverSpy contains method joinInformationSource

但在您的代码中，您使用 joinInformationSource 作为字段

// _join.joinInformationSource has been used as a field

this._join.joinInformationSource.pipe(filter(x => x !== null)).subscribe(result => {
    this.joinInformation = result;
    this.setFields(result.userInfo);
});

因为joinInformationSource 是一个函数，所以它肯定没有pipe 方法。解决方案很少。其中之一是使用spyOnProperty 方法：

//create a service object and define a property

const joinService: any = new Object();
Object.defineProperty(joinService, 'joinInformationSource', {get: () => {}});

//then create a spy on the property

it('should prepopulate fields if there is join information', () => {
    let joinInfoSpy = spyOnProperty(joinService, 'joinInformationSource', 'get')
        .and.returnValue(
            new BehaviorSubject<JoinInformation>(//object)
        )
    }
    //the rest of the code
);