Angular Dependency Injection - @Injectable()在测试中失败,而@Inject()工作

Question

一般问题

我刚刚开始将带有角度5的webpacker添加到现有的rails应用程序中.一切都很好,除了测试DI的奇怪问题.

看来我的Angular组件在使用浏览器创建时才起作用,但在使用Jasmine/Karma进行测试时,Dependency Injector无法识别注入令牌.使用伪代码:

@Component({...})
export class SomeComponent {
  constructor(private service: SomeService) {}
}

以上工作在浏览器中,但正在Error: Can't resolve all parameters for SomeComponent: (?).测试中.到目前为止,我注意到它适用于所有@Injectable(),但是一旦我用显式的@Inject替换每个注入:

@Component({...})
export class SomeComponent {
  constructor(@Inject(SomeService) private service: SomeService) {}
}

一切正常(但显然是非常麻烦).有什么明显可能导致这种情况吗？

实际代码

我有一个非常简单的服务与HttpClient一起运行:

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

import 'rxjs/add/operator/map'

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

  getMinDate() {
    return this.http.get("/api/v1/general_stats/min_date")
      .map(r => new Date(r))
  }
}

当我导航到使用所述服务的组件时,它按预期工作.但是,在使用Jasmine进行测试时,它不起作用:

import { TestBed } from "@angular/core/testing";
import { HttpClientTestingModule, HttpTestingController } from "@angular/common/http/testing";
import { GeneralStatsService } from "./general-stats.service";


describe('GeneralStatsService', () => {
  let service : GeneralStatsService;
  let httpMock : HttpTestingController;

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

  beforeEach(() => {
    service = TestBed.get(GeneralStatsService);
    httpMock = TestBed.get(HttpTestingController);
  });

  afterEach(() => {
    httpMock.verify();
  });

  describe('getMinDate()', () => {
    let fakeResponse : string = "2015-03-05T12:39:11.467Z";

    it('returns instance of Date', (done) => {
      service.getMinDate().subscribe((result : Date) => {
        expect(result.getFullYear()).toBe(2015);
        expect(result.getMonth()).toBe(2); // January is 0
        expect(result.getDate()).toBe(5);
        done();
      });

      const req = httpMock.expectOne("/api/v1/general_stats/min_date");
      expect(req.request.method).toBe('GET');
      req.flush(fakeResponse);
    })
  });
});

如上所述,添加显式@Inject(HttpClient)修复测试,但我宁愿避免这种情况.

组态

噶:

const webpackConfig = require('./config/webpack/test.js');

module.exports = function(config) {
  config.set({
    basePath: '',
    frameworks: [ 'jasmine' ],
    plugins: [
      require('karma-webpack'),
      require('karma-jasmine'),
      require('karma-chrome-launcher'),
      require('karma-jasmine-html-reporter'),
      require('karma-coverage-istanbul-reporter'),
      require('karma-spec-reporter')
    ],
    files: [
      'config/webpack/angular-bundle.ts'
    ],
    webpack: webpackConfig,
    preprocessors: {
      'config/webpack/angular-bundle.ts': ["webpack"]
    },
    mime: { "text/x-typescript": ["ts"]},
    coverageIstanbulReporter: {
      reports: [ 'html', 'lcovonly' ],
      fixWebpackSourcePaths: true
    },
    client: { clearContext: false },

    reporters: [ 'progress', 'kjhtml', 'coverage-istanbul' ],
    port: 9876,
    colors: true,

    logLevel: config.LOG_INFO,
    autoWatch: true,
    browsers: [ 'Chrome' ],
    singleRun: false,
    concurrency: Infinity
  })
};

配置/的WebPack/test.js:

const environment = require('./environment');
environment.plugins.get('Manifest').opts.writeToFileEmit = process.env.NODE_ENV !== 'test';
environment.loaders.set('istanbul-instrumenter', {
  test: /\.ts$/,
  enforce: 'post',
  loader: 'istanbul-instrumenter-loader',
  query: {
    esModules: true
  },
  exclude: ["node_modules", /\.spec.ts$/]
});

module.exports = environment.toWebpackConfig()

配置/的WebPack /角bundle.ts:

import 'zone.js/dist/zone'
import 'zone.js/dist/long-stack-trace-zone';
import 'zone.js/dist/proxy.js';
import 'zone.js/dist/sync-test';
import 'zone.js/dist/jasmine-patch';
import 'zone.js/dist/async-test';
import 'zone.js/dist/fake-async-test';
import { getTestBed } from '@angular/core/testing';
import {
    BrowserDynamicTestingModule,
    platformBrowserDynamicTesting
} from '@angular/platform-browser-dynamic/testing';

declare const require: any;

jasmine.MAX_PRETTY_PRINT_DEPTH = 3;

getTestBed().initTestEnvironment(
    BrowserDynamicTestingModule,
    platformBrowserDynamicTesting()
);

const context = (require as any).context('../../app/javascript', true, /\.spec\.ts$/);
context.keys().map(context);

tsconfig.json:

{
  "compilerOptions": {
    "declaration": false,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "lib": ["es6", "dom"],
    "module": "es6",
    "moduleResolution": "node",
    "sourceMap": true,
    "target": "es5"
  },
  "exclude": [
    "**/*.spec.ts",
    "node_modules",
    "vendor",
    "public",
    "config/**/*.ts"
  ],
  "compileOnSave": false
}

environment.js:

const environment = require('@rails/webpacker').environment;

const typescript =  require('./loaders/typescript');
const erb =  require('./loaders/erb');
const elm =  require('./loaders/elm');
const html =  require('./loaders/html');

environment.loaders.append('elm', elm);
environment.loaders.append('erb', erb);
environment.loaders.append('typescript', typescript);
environment.loaders.append('html', html);

module.exports = environment;

以防万一,装载机/打字稿:

module.exports = {
  test: /\.(ts|tsx)?(\.erb)?$/,
  use: [{
    loader: 'ts-loader'
  }]
}

Answer 1

尝试使用注射器和间谍。

您必须创建一个没有“HttpClient”的模拟服务，该服务具有您想要模拟的服务的所有方法。然后用spyOn你就可以返回你想要的东西。

TestBed.configureTestingModule({
      imports: [
        FormsModule,
        BrowserAnimationsModule
      ],
      providers: [
        {
          provide: YourService,
          useValue: mockedYourService
        }
      ]
      ....

 beforeEach(() => {
   fixture = TestBed.createComponent(YourTestingComponent);
   component = fixture.componentInstance;
   element = fixture.nativeElement;
   fixture.detectChanges();
 });

 ...
      
describe('methodName', () => {
  it('message to print',
    () => {
      const your_Service = fixture.debugElement.injector.get(YourService);
      spyOn(your_Service, 'methodName').and.returnValue(true);
        
        .....

希望这有帮助！