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我对Angular4相当陌生,需要为我构建的简单服务编写单元测试,但不知道从哪里开始。Angular4 - 如何测试一个服务
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { HttpClient } from '@angular/common/http';
import 'rxjs/add/operator/map';
import { KeyValuePair } from '../../models/keyvaluepair';
import { environment } from './../../../environments/environment';
// Lookups api wrapper class.
@Injectable()
export class LookupsService {
private servicegApiUrl = '';
public constructor(private http : HttpClient) {
// Build the service api url, uring the environment lookups api url, plus controller name to reference.
this.servicegApiUrl = environment.webApiUrl + 'Lookups/';
}
// Get the hubs from the web api.
public getHubs() : Observable<KeyValuePair<number>[]> {
// Carry out http get and map the result to the KeyValuePair number object.
return this.http.get<KeyValuePair<number>[]>(this.servicegApiUrl + 'Hubs').map(res => { return res; });
}
}
我需要测试我getHubs()方法,不知道如何:
服务仅仅如下包装API调用。另外,我在网上看到过有关测试服务的各种文章,我不确定是否需要嘲笑预期的结果,或者是否应该实际调用Web服务。我有这样的代码,但预期似乎从来没有得到执行:
import { TestBed, async, inject } from '@angular/core/testing';
import { HttpClientModule, HttpRequest, HttpParams } from '@angular/common/http';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { LookupsService } from './Lookups.Service';
import { KeyValuePair } from './../../models/KeyValuePair';
describe(`LookupsService tests`,() => {
beforeEach(() => {
TestBed.configureTestingModule({
imports: [
HttpClientModule,
HttpClientTestingModule
],
providers: [
LookupsService
]
});
});
it(`should get results from the web method`, async(inject([ LookupsService, HttpTestingController ],
(service: LookupsService, backend: HttpTestingController) => {
service.getHubs().subscribe((hubs : KeyValuePair<number>[]) => {
// This code never seems to run...
console.log(hubs.length);
expect(hubs.length).toBeGreaterThan(0);
});
})));
});
为了完整KeyValuePair类看起来是这样的:
export class KeyValuePair<T> {
Key : string;
Value : T;
}
任何帮助,非常感谢!
好酷 - 所以最好测试时不依赖于真正的api。所以我嘲笑实际的电话。有没有人用HttpClient作为依赖模拟结果测试服务的好例子? –
你总是可以尝试使用'spyOn'来窥探一种方法。检查此答案的用法:https://stackoverflow.com/questions/30658525/spy-on-a-service-method-call-using-jasmine-spies – eminlala