Jasmine Testing Subscription To Service Level Observable From OnInit Angular

Question

I am working on testing a component which has a subscription within the ngOnInit method. Works fine when running in "the wild" but testing fails as there is no subscription object available. I have tried creating a stub svc to build the observable object within my unit test, but can't get it to work.

Here's my Service and Component code (abrv):

Component

  ngOnInit() {
   this.userSvc.user.subscribe(user => {
    this.currentUser = user; //-- this.userSvc.user (which is an observable on that class) is available in the wild, but not when testing
   })
  }

UserService

  //-- User Subscribe items
  userSubject: BehaviorSubject<any> = new BehaviorSubject(null);
  user = this.userSubject.asObservable(); // this is the property I'm subscribing to which gets set after login.

Here is my Test Setup

//SvcStub
const usrSvcStub = {
 user : {
  FirstName: "Test",
  LastName: "User",
  Username: "testuser"
 }
}

//Providers Config
 providers: [
    {provide: UserService, useValue: {usrSvcStub}}
   ]

When the test fires, I can see through debug that it is loading my "StubSvc" but user is undefined and I cannot subscribe to it. Can someone point me in right direction? Screenie below shows when it loads the component's ngOnInit function and subscribes to the service observable.

Answer 1

Can you try

const usrSvcStub = {
 user : new BehaviorSubject<any>({
  FirstName: "Test",
  LastName: "User",
  Username: "testuser"
 })
}