无法编写带有marbel测试的测试用例

Question

我之所以创建这个函数，是因为对于我的应用程序使用http.post发送的所有请求，这就是不同部分处理响应的方式。因此，我没有复制代码，而是想创建一个函数。我想模拟错误处理，并考虑使用marbel testing。尽管我可以看到测试用例emits是一条错误消息，但测试仍然失败。我做错了什么

private editAnswerSubject: Subject<Result>;
subscribeToReturnedObservable(observable:Observable<any>, subject:Subject<Result>) {
observable.subscribe((res) => {
const ev = <HttpEvent<any>>(res);
if (ev.type === HttpEventType.Response) {
const isResponseStructureOK: boolean = this.helper.validateServerResponseStructure(ev.body);
if (isResponseStructureOK) {
const response: ServerResponseAPI = ev.body;
subject.next(new Result(response.result, response['additional-info']));
} else {
subject.next(new Result(messages.error, messages.invalidStructureOfResponse));
}
}
},
(error: ServerResponseAPI) => { //THIS IS THE CODE I WANT TO TEST
const errorMessage: string = this.helper.userFriendlyErrorMessage(error);
subject.next(new Result(messages.error, errorMessage));    
},
() => { // observable complete
});
}
editAnswer(answer: Answer): any {
const observable = this.bs.editAnswer(answer)
this.subscribeToReturnedObservable(observable,this.editAnswerSubject);
}

到目前为止，我写的测试是

fit('should call next for the subject if the response from the server is error', () => {
const questionService:QuestionManagementService = TestBed.get(QuestionManagementService);
const serverErrorResponse = {
result: "error",
['additional-info']: "reason for error",
['http-status']: "304",
['http-status-text']: "not found"
};
const testScheduler = new TestScheduler((actual,expected)=>{
expect(actual).toEqual(expected);
});
spyOn(questionService['editQuestionSubject'],'next');
testScheduler.run(helpers=>{
const { cold, expectObservable, expectSubscriptions } = helpers;
const expectedMarble = '#|';//error
const expectedIngridients = {a:serverErrorResponse};
const observable = cold(expectedMarble,{},serverErrorResponse);
questionService.subscribeToReturnedObservable(observable,questionService['editQuestionSubject']);
const expectedResult = new Result(messages.error, 'Error code: 304. not found. error: reason for error');
expect(questionService['editQuestionSubject'].next).toHaveBeenCalledWith(expectedResult);
});

但它得到错误Expected spy next to have been called with [ Result({ result: 'error', additionalInfo: 'Error code: 304. not found. error: reason for error' }) ] but it was never called.

我可以在代码跟踪中看到收到了错误值。

subscribeToReturnedObservable called
got error from the Observable:  {result: "error", additional-info: "reason for error", http-status: "304", http-status-text: "not found"}

Answer 1

我不得不调用flush。老实说，我不知道它为什么以及如何让事情运转起来。从我能理解的原因来看，我正在以同步的方式测试。因此，我需要调用flush，以便在Observable完成时调用断言(expect(。

fit('should call next for the subject if the response from the server is error', () => {
const questionService:QuestionManagementService = TestBed.get(QuestionManagementService);
const serverErrorResponse = {
result: "error",
['additional-info']: "reason for error",
['http-status']: "304",
['http-status-text']: "not found"
};
const testScheduler = new TestScheduler((actual,expected)=>{
expect(actual).toEqual(expected);
});
spyOn(questionService['editQuestionSubject'],'next');
testScheduler.run(helpers=>{
const { cold, expectObservable, expectSubscriptions,flush } = helpers;
const expectedMarble = '#|';//error
// const expectedIngridients = {a:serverErrorResponse};
const observable = cold(expectedMarble,null,serverErrorResponse);
questionService.subscribeToReturnedObservable(observable,questionService['editQuestionSubject']);
flush(); //THIS
const expectedResult = new Result(messages.error, 'Error code: 304. not found. error: reason for error');
expect(questionService['editQuestionSubject'].next).toHaveBeenCalledWith(expectedResult);
});
});