Ionic3 - Testing. Test if a Page is pushed on the NavigationStack - testing

Question

Im really new to Testing. I set up TedBed. Now i try to test my first Component "MyApp" which looks like this:
#Component({
templateUrl: 'app.html'
})
export class MyApp implements OnInit {
rootPage:any = HomePage;
constructor(
private app:App,
) {
}
pageTwo() {
let navs = this.app.getActiveNavs();
let nav = navs[0]
nav.push(AnotherPage);
}
ngOnInit() {
}
}
Template:
<ion-menu [content]="content" persistent="true">
<ion-header>
<ion-navbar>
<ion-title>
MyApp
</ion-title>
</ion-navbar>
</ion-header>
<ion-content>
<ion-list>
<button menuClose (click)="pageTwo()" ion-item>
<ion-label>
AnotherPage
</ion-label>
</button>
</ion-list>
</ion-content>
</ion-menu>
<ion-nav [root]="rootPage" #content swipeBackEnabled="false"></ion-nav>
As you can see i, i have a mehtod that navigate to "AnotherPage" if the menu-button is clicked. This is working - Now i try to test this behavior:
describe('MyApp Component', () => {
let fixture;
let component;
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [MyApp],
imports: [
IonicModule.forRoot(MyApp),
],
providers: [
{provide: NavController, useFactory: () => NavControllerMock.instance()},
{provide: App, useFactory: () => AppMock.instance()},
]
})
}));
beforeEach(() => {
fixture = TestBed.createComponent(MyApp);
fixture.detectChanges();
component = fixture.componentInstance;
});
it('should be created', () => {
expect(component instanceof MyApp).toBe(true);
});
it('should navigate to Antoherpage if pageTwo() is called', () => {
component.pageTwo()
// ...
});
});
I have no clue what i have to do, to test if the "AnotherPage" is pushed to the Navstack after method "pageTwo" is called.
Thanks in advance

Answer 1

So, after some research i got it working. It was easier than i thought:
it('should navigate to Antoherpage if pageTwo() is called', () => {
component.pageTwo()
expect(nav.push).toHaveBeenCalledWith(AnotherPage);
});
since i use the ionic-mocks package (https://github.com/stonelasley/ionic-mocks). I dont have to spy on the nav.push manually.