title: How to unit test an IntervalObservable
body: <p>In my Angular app, I make use of an <a href="http://reactivex.io/rxjs/class/es6/observable/IntervalObservable.js~IntervalObservable.html" rel="nofollow noreferrer">IntervalObservable</a> in order to periodically perform some actions (in my case every 
  5 minutes):</p>
  
  <pre><code>IntervalObservable.create(300000) // 5 minutes
    .subscribe(() =&gt; {
      this.someMethodReturningObs().subscribe((data) =&gt; {
        this.myData = data;
      });
    });
  </code></pre>
  
  <p>how I can unit test it?</p>