即使成功，如何避免“错误：规范方法没有期望”？

Question

我有 Angular HTTP 服务，可以进行一些 HTTP 调用。 这是我的服务示例：

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Injectable()
export class APIService {
    constructor(private readonly http: HttpClient) {}

    public async getUsers<T>(): Promise<T[]> {
        return await this.http.get<T[]>('/api/users').toPromise();
    }
}

这是我的spec.ts 文件APIService：

import { TestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { APIService } from './api.service';

describe('API Service', () => {
    let service: APIService;
    let controller: HttpTestingController;

    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [HttpClientTestingModule],
            providers: [APIService]
        });

        service = TetsBed.get(APIService);
        controller = TestBed.get(HttpTestingController);
    });

    it('should create the API service', () => {
        expect(service).toBeTruthy();
    });

    it('should get users', () => {
        const expected = [{id: 1, email: 'email1@domain.tld'},
                          {id: 2, email: 'email2@domain.tld'}];

        service.getUsers<MyUserClass>().then((res) => {
            expect(res).toEqual(expected);
            controller.verify();
        });

        controller.expectOne('/api/users').flush(expected);
    });

});

似乎一切正常，因为当我运行 ng test 时，我收到这样的消息：

ERROR: 'Spec 'API Service should get users' has no expectations.'
HeadlessChrome 77.0.3865 (Windows 10.0.0): Executed 13 of 15 SUCCESS (0 secs / 0.256 secs)
HeadlessChrome 77.0.3865 (Windows 10.0.0): Executed 15 of 15 SUCCESS (0.42 secs / 0.28 secs)
TOTAL: 15 SUCCESS
TOTAL: 15 SUCCESS
TOTAL: 15 SUCCESS

当我在下一个代码下更改某些内容时，我得到了错误。

.then((res) => {
    // expect(res).toEqual(expected);
    expect(res).toBeNull();
    controller.verify();
});

所以上面的代码很好并且可以工作。

那么，为什么我会收到一条错误消息：ERROR: 'Spec 'API Service should get users' has no期望。'？有什么想法吗？

我猜，async/await 可能会导致这个问题，因为我实际上并没有等待它，但是它执行时没有错误，当我输入错误的数据时，它就会失败。

我还尝试将所有内容包装到 async/fakeAsync 方法中 - 不走运。

Answer 1

嗯，实际上(done) 解决了我的问题；

import { TestBed } from '@angular/core/testing';
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';
import { APIService } from './api.service';

describe('API Service', () => {
    let service: APIService;
    let controller: HttpTestingController;

    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [HttpClientTestingModule],
            providers: [APIService]
        });

        service = TetsBed.get(APIService);
        controller = TestBed.get(HttpTestingController);
    });

    it('should create the API service', () => {
        expect(service).toBeTruthy();
    });

    it('should get users', (done) => {
        const expected = [{id: 1, email: 'email1@domain.tld'},
                          {id: 2, email: 'email2@domain.tld'}];

        service.getUsers<MyUserClass>().then((res) => {
            expect(res).toEqual(expected);
            controller.verify();
            done();
        });

        controller.expectOne('/api/users').flush(expected);
    });

});