Observable.fromPromise empty during unit testing

Question

loadAdList$ is an Observable that taps into the actions$ stream:

loadAdList$: Observable = this.actions$
    .ofType&         


        

Answer 1

It is bit unfortunate but there wasn't great way to make promise resolves synchronously under context of TestScheduler in Rx v5. For those reason, if Observable source started off from promise it won't work with marble testings and you have to create assertion differently by subscribing.

Check https://github.com/ReactiveX/rxjs/issues/701 / https://github.com/ReactiveX/rxjs/pull/745 if you'd like to have detail why it wasn't successful.