Angular2 / ng test ERROR: 'Unhandled Promise rejection'

I currently work on angular2 project with angullar-cli. Since tomorow, i get a new error from ng test command, the trace below. This error is triggered every time i run ng test command. I identify the code in spec.ts whitch raise the error :

const fakeRouter = jasmine.createSpyObj('Router', ['navigate']);
beforeEach(() => TestBed.configureTestingModule({
    imports: [AppModule, RouterTestingModule],
    providers: [{ provide: Router, useValue: fakeRouter }]
 }));

When I remove the provider router, the error disapear. However, all my tests pass successfull.

My angular-cli version :

angular-cli: 1.0.0-beta.32.3 node: 6.7.0 os: win32 x64

ERROR :

ERROR: 'Unhandled Promise rejection:', 'Cannot set property 'afterPreactivation' of undefined', '; Zone:', 'ProxyZone', '; Task:', 'Promise.then', '; Value:', TypeError{}, 'TypeError: Cannot set property 'afterPreactivation' of undefined
        at http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:66907:49
        at ZoneDelegate.invoke (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94256:26)
        at ProxyZoneSpec.onInvoke (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:70192:39)
        at ZoneDelegate.invoke (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94255:32)
        at Zone.run (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94052:43)
        at http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94605:57
        at ZoneDelegate.invokeTask (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94289:31)
        at ProxyZoneSpec.onInvokeTask (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:70216:39)
        at ZoneDelegate.invokeTask (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94288:36)
        at Zone.runTask (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94092:47)
        at drainMicroTaskQueue (http://localhost:9876/base/src/test.ts?10abbba6756b062e1f8ba4c1873d1f257bc67f65:94455:35)