Angular2 快速入门教程打破了 Karma 测试 - “无法绑定到'ngModel'，因为它不是'input'的已知属性。”

在尝试 TDD 时，我正在关注官方的 Angular“Hero”快速入门教程。

https://angular.io/docs/ts/latest/tutorial/toh-pt1.html

一旦我到达替换步骤：

<input value="{{hero.name}}" placeholder="name">

同

<input [(ngModel)]="hero.name" placeholder="name">

我的 Karma 测试运行器抛出以下错误：

错误：模板解析错误：无法绑定到'ngModel'，因为它不是'input'的已知属性.(“name：] [7] =”hero.name“placeholder =”name“>”)：AppComponent@6:23 预期未定义要定义.

但是，应用程序按预期工作，我在控制台中看不到任何错误。 (而且我相当自信我正确地遵循了教程，看不到任何拼写错误等)

我的 app.components.ts 看起来像：

import { Component } from '@angular/core';

export class Hero {
    id: number;
    name: string;
}

@Component({
    selector: 'my-app',
    template: `
            <h1>{{title}}</h1>
            <h2>{{hero.name}} details!</h2>
            <div><label>id: </label>{{hero.id}}</div>
            <div>
                <label>name: </label>
                <input [(ngModel)]="hero.name" placeholder="name">
            </div>
    `
})

export class AppComponent {
    title = 'Tour of Heroes';
    hero: Hero = {
        id: 1,
        name: 'Windstorm'
    };
}

我的 app.module 看起来像：

import { NgModule }      from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent }   from './app.component';
import { FormsModule }   from '@angular/forms';

@NgModule({
  imports:      [ BrowserModule, FormsModule],
  declarations: [ AppComponent],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

从模板中删除 ngModel 后，Karma 工作正常，正如我之前所说，实际应用程序的行为符合预期。在广泛的谷歌搜索后，我似乎无法找到任何与我的问题有关的信息:(

我的 karma.config 是标准的快速启动：

// #docregion
module.exports = function(config) {

  var appBase    = 'app/';       // transpiled app JS and map files
  var appSrcBase = 'app/';       // app source TS files
  var appAssets  = 'base/app/'; // component assets fetched by Angular's compiler

  var testBase    = 'testing/';       // transpiled test JS and map files
  var testSrcBase = 'testing/';       // test source TS files

  config.set({
    basePath: '',
    frameworks: ['jasmine'],
    plugins: [
      require('karma-jasmine'),
      require('karma-chrome-launcher'),
      require('karma-jasmine-html-reporter'), // click "Debug" in browser to see it
      require('karma-htmlfile-reporter') // crashing w/ strange socket error
    ],

    customLaunchers: {
      // From the CLI. Not used here but interesting
      // chrome setup for travis CI using chromium
      Chrome_travis_ci: {
        base: 'Chrome',
        flags: ['--no-sandbox']
      }
    },
    files: [
      // System.js for module loading
      'node_modules/systemjs/dist/system.src.js',

      // Polyfills
      'node_modules/core-js/client/shim.js',
      'node_modules/reflect-metadata/Reflect.js',

      // zone.js
      'node_modules/zone.js/dist/zone.js',
      'node_modules/zone.js/dist/long-stack-trace-zone.js',
      'node_modules/zone.js/dist/proxy.js',
      'node_modules/zone.js/dist/sync-test.js',
      'node_modules/zone.js/dist/jasmine-patch.js',
      'node_modules/zone.js/dist/async-test.js',
      'node_modules/zone.js/dist/fake-async-test.js',

      // RxJs
      { pattern: 'node_modules/rxjs/**/*.js', included: false, watched: false },
      { pattern: 'node_modules/rxjs/**/*.js.map', included: false, watched: false },

      // Paths loaded via module imports:
      // Angular itself
      { pattern: 'node_modules/@angular/**/*.js', included: false, watched: false },
      { pattern: 'node_modules/@angular/**/*.js.map', included: false, watched: false },

      { pattern: 'systemjs.config.js', included: false, watched: false },
      { pattern: 'systemjs.config.extras.js', included: false, watched: false },
      'karma-test-shim.js',

      // transpiled application & spec code paths loaded via module imports
      { pattern: appBase + '**/*.js', included: false, watched: true },
      { pattern: testBase + '**/*.js', included: false, watched: true },

      // Asset (HTML & CSS) paths loaded via Angular's component compiler
      // (these paths need to be rewritten, see proxies section)
      { pattern: appBase + '**/*.html', included: false, watched: true },
      { pattern: appBase + '**/*.css', included: false, watched: true },

      // Paths for debugging with source maps in dev tools
      { pattern: appSrcBase + '**/*.ts', included: false, watched: false },
      { pattern: appBase + '**/*.js.map', included: false, watched: false },
      { pattern: testSrcBase + '**/*.ts', included: false, watched: false },
      { pattern: testBase + '**/*.js.map', included: false, watched: false }
    ],

    // Proxied base paths for loading assets
    proxies: {
      // required for component assets fetched by Angular's compiler
      "/app/": appAssets
    },

    exclude: [],
    preprocessors: {},
    // disabled HtmlReporter; suddenly crashing w/ strange socket error
    reporters: ['progress', 'kjhtml'],//'html'],

    // HtmlReporter configuration
    htmlReporter: {
      // Open this file to see results in browser
      outputFile: '_test-output/tests.html',

      // Optional
      pageTitle: 'Unit Tests',
      subPageTitle: __dirname
    },

    port: 9876,
    colors: true,
    logLevel: config.LOG_INFO,
    autoWatch: true,
    browsers: ['Chrome'],
    singleRun: false
  })
}

谁能帮我？