title: How to test ngrx pipe select in Rxjs 6
body: <p>Previously I could test the below store select </p>
  
  <pre><code>this.store.select(fromRoot.someselector).pipe(map(r =&gt; this.store.dispatch(new Action())));
  </code></pre>
  
  <p>This was in my test</p>
  
  <pre><code>{provide: Store, useValue: jasmine.createSpyObj('store', ['select']);
  
  store.select.and.returnValue(of({}));
  </code></pre>
  
  <p>But now it has changed to pipes</p>
  
  <pre><code>this.store.pipe(select(fromRoot.someselector));
  
  this.store.pipe(
          select(fromRoot.someselector), 
          filter(result =&gt; !!result), 
          map(r =&gt; { 
               if (result === ' hello') { 
                 this.store.dispatch(new Action()); 
               } 
             }
          ));
  </code></pre>
  
  <p>How to test this especially when you have map after select and within it you are dispatching an action and you want verify action was called.</p>