I am unit testing a component that is used to edit an object. The object has an unique id
that is used in order to grab the specific object from an array of obj
In angular 8+ there is the RouterTestingModule, which you can use in order to have access to the ActivatedRoute or Router of the component. Also you can pass routes to the RouterTestingModule and create spies for the requested methods of route.
For example in my component I have:
ngOnInit() {
if (this.route.snapshot.paramMap.get('id')) this.editMode()
this.titleService.setTitle(`${this.pageTitle} | ${TAB_SUFFIX}`)
}
And in my test I have:
beforeEach(async(() => {
TestBed.configureTestingModule({
declarations: [ ProductLinePageComponent ],
schemas: [NO_ERRORS_SCHEMA],
imports: [
RouterTestingModule.withRoutes([])
],
})
.compileComponents()
}))
beforeEach(() => {
router = TestBed.get(Router)
route = TestBed.get(ActivatedRoute)
})
and later in the 'it' section:
it('should update', () => {
const spyRoute = spyOn(route.snapshot.paramMap, 'get')
spyRoute.and.returnValue('21')
fixture = TestBed.createComponent(ProductLinePageComponent)
component = fixture.componentInstance
fixture.detectChanges()
expect(component).toBeTruthy()
expect(component.pageTitle).toBe('Edit Product Line')
expect(component.formTitle).toBe('Edit Product Line')
// here you can test the functionality which is triggered by the snapshot
})
In a similar way, I think you can test directly the paramMap via the spyOnProperty method of jasmine, by returning an observable or using rxjs marbles. It might save some time & also it does not require to maintain an extra mock class. Hope that it is useful and it makes sense.