Angular 4 Error: No provider for ChildrenOutletContexts in Karma-Jasmine Test

Question

My Angular application is working properly, but I am keep getting Karma error when I run ng test command. I have attached app component, spec, module and html along with package.json file. Error looks like this:

Failed: No provider for ChildrenOutletContexts!
Error: No provider for ChildrenOutletContexts!
at injectionError (http://localhost:9876/_karma_webpack_/vendor.bundle.js:39523:90)
at noProviderError (http://localhost:9876/_karma_webpack_/vendor.bundle.js:39561:12)
at ReflectiveInjector_.webpackJsonp.../../../core/@angular/core.es5.js.ReflectiveInjector_._throwOrNull (http://localhost:9876/_karma_webpack_/vendor.bundle.js:41003:19)
at ReflectiveInjector_.webpackJsonp.../../../core/@angular/core.es5.js.ReflectiveInjector_._getByKeyDefault (http://localhost:9876/_karma_webpack_/vendor.bundle.js:41042:25)
at ReflectiveInjector_.webpackJsonp.../../../core/@angular/core.es5.js.ReflectiveInjector_._getByKey (http://localhost:9876/_karma_webpack_/vendor.bundle.js:40974:25)
at ReflectiveInjector_.webpackJsonp.../../../core/@angular/core.es5.js.ReflectiveInjector_.get (http://localhost:9876/_karma_webpack_/vendor.bundle.js:40843:21)
at resolveNgModuleDep (http://localhost:9876/_karma_webpack_/vendor.bundle.js:47827:25)
at NgModuleRef_.webpackJsonp.../../../core/@angular/core.es5.js.NgModuleRef_.get (http://localhost:9876/_karma_webpack_/vendor.bundle.js:48909:16)
at resolveDep (http://localhost:9876/_karma_webpack_/vendor.bundle.js:49412:45)
at createClass (http://localhost:9876/_karma_webpack_/vendor.bundle.js:49276:32)

app.component.ts

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

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.less']
})
export class AppComponent {
  title = 'app';
}

app.component.html

<a href="http://localhost:4200/dashboard">Dashboard</a>
<a href="http://localhost:4200/user">User</a> 
<router-outlet></router-outlet>

app.component.spec.ts

import { TestBed, async } from '@angular/core/testing';
import { RouterModule, Routes } from '@angular/router';
import { FormsModule } from '@angular/forms';
import { APP_BASE_HREF } from '@angular/common';

import { AppComponent } from './app.component';
import { DashboardComponent } from './modules/dashboard/dashboard.component';

describe('AppComponent', () => {
  const routes: Routes = [
    {
      path: '',
      redirectTo: 'dashboard',
      pathMatch: 'full'
    },
    {
      path: 'dashboard',
      component: DashboardComponent,
    },
    {
      path: 'user',
      loadChildren: 'app/modules/user/user.module#UserModule'
    }
  ];

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        RouterModule,
        FormsModule
      ],
      declarations: [
        AppComponent,
        DashboardComponent
      ],
      providers: [
        { provide: APP_BASE_HREF, useClass: routes }
      ]
    }).compileComponents();
  }));

  it('should create the app', async(() => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.debugElement.componentInstance;
    expect(app).toBeTruthy();
  }));

  it('should have as title app', async(() => {
    const fixture = TestBed.createComponent(AppComponent);
    const app = fixture.debugElement.componentInstance;
    expect(app.title).toEqual('app');
  }));

  it('should render title in a h1 tag', async(() => {
    const fixture = TestBed.createComponent(AppComponent);
    fixture.detectChanges();
    const compiled = fixture.debugElement.nativeElement;
    expect(compiled.querySelector('h1').textContent).toContain('Welcome to app!!');
  }));
});

app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { RouterModule, Routes } from '@angular/router';

import { AppComponent } from './app.component';
import { DashboardComponent } from './modules/dashboard/dashboard.component';

const routes: Routes = [
  {
    path: '',
    redirectTo: 'dashboard',
    pathMatch: 'full'
  },
  {
      path: 'dashboard', 
      component: DashboardComponent, 
  },
  {
    path: 'user',
    loadChildren: 'app/modules/user/user.module#UserModule'
  }
];

@NgModule({
  declarations: [
    AppComponent,
    DashboardComponent,
  ],
  imports: [
    BrowserModule,
    FormsModule,
    RouterModule.forRoot(routes)
  ],
  providers: [],
  bootstrap: [AppComponent],
  exports: [RouterModule]
})
export class AppModule { }

package.json

    ...
 "dependencies": {
    "@angular/animations": "^4.0.0",
    "@angular/common": "^4.0.0",
    "@angular/compiler": "^4.0.0",
    "@angular/core": "^4.0.0",
    "@angular/forms": "^4.0.0",
    "@angular/http": "^4.0.0",
    "@angular/platform-browser": "^4.0.0",
    "@angular/platform-browser-dynamic": "^4.0.0",
    "@angular/router": "^4.0.0",
    "core-js": "^2.4.1",
    "rxjs": "^5.1.0",
    "zone.js": "0.8.12"
  },
  "devDependencies": {
    "@angular/cli": "1.2.1",
    "@angular/compiler-cli": "^4.0.0",
    "@angular/language-service": "^4.0.0",
    "@types/jasmine": "~2.5.53",
    "@types/jasminewd2": "~2.0.2",
    "@types/node": "~6.0.60",
    "codelyzer": "~3.0.1",
    "jasmine-core": "~2.6.2",
    "jasmine-spec-reporter": "~4.1.0",
    "karma": "~1.7.0",
    "karma-chrome-launcher": "~2.1.1",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^1.2.1",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.2",
    "ts-node": "~3.0.4",
    "tslint": "~5.3.2",
    "typescript": "~2.3.3",
....

Answer 1

Based on the clue provided by @John, I imported RouterTestingModule instead of importing RouterModule and APP_BASE_HREF. So, the following modification in app.component.spec.ts worked!

import { TestBed, async } from '@angular/core/testing';
import { FormsModule } from '@angular/forms';
import { RouterTestingModule } from '@angular/router/testing';

import { AppComponent } from './app.component';
import { DashboardComponent } from './modules/dashboard/dashboard.component';

describe('AppComponent', () => {
  beforeEach(async(() => {
    TestBed.configureTestingModule({
      imports: [
        RouterTestingModule 
        FormsModule
      ],
      declarations: [
        AppComponent,
        DashboardComponent
      ]
    }).compileComponents();
  }));