"Navigation triggered outside Angular zone" warning in unit tests

I’m submitting a…

[x] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Performance issue
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[ ] Other... Please describe:

Current behavior

Using the last Angular 6.1.7 which introduced a warning if a navigation is triggered outside a zone (see https://github.com/angular/angular/commit/010e35d99596e1b35808aaaeecfc32f3b247a7d8), a simple unit test calling router.navigate yields the warning (resulting in hundreds of warnings in the console).

Expected behavior

The warning should not be emitted in unit tests. It’s currently possible to remove it by using zone.run or using NoopNgZone, but this is cumbersome. A way to disable it in unit tests would be great.

Minimal reproduction of the problem with instructions

Build a minimal app with the CLI

ng new router-warning --routing

Then replace the default unit test with:

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

import { AppComponent } from './app.component';

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

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

Run ng test, and the following warning should appear:

WARN: 'Navigation triggered outside Angular zone, did you forget to call 'ngZone.run()'?'

Environment

Angular version: 6.1.7 or 7.0.0-beta.5

Browser:
- [x] Chrome (desktop) version XX
- [ ] Chrome (Android) version XX
- [ ] Chrome (iOS) version XX
- [ ] Firefox version XX
- [ ] Safari (desktop) version XX
- [ ] Safari (iOS) version XX
- [ ] IE version XX
- [ ] Edge version XX
 
For Tooling issues:
- Node version: 8.11.3
- Platform:  Mac

cc @trotyl

[ItzhakBokris]

Workaround:

constructor(private ngZone: NgZone, private router: Router) {}

public navigate(commands: any[]): void {
    this.ngZone.run(() => this.router.navigate(commands)).then();
}

[CharlyRipp]

In unit test:

it('should just work', async(() => {
    fixture.ngZone.run(() => {
        router.navigate(['path1']);
        fixture.detectChanges();
        fixture.whenStable().then(() => {
            expect({stuff}).toHaveBeenCalled();
        });
    });
}));