title: click on a tab inside ts file
body: <p>I am performing an e2e testing, Here i need to open the tabs which are not present in html file it is located in ts file as a template</p>
  
  <pre><code>import {soPage}                 from    './soList.ts';
  import {poPage}                 from    './poList.ts';
  
  @Page({
  
      template : 
          `&lt;ion-tabs primary  class="tabs" id="tabs" selectedIndex="1"&gt;
              &lt;ion-tab [root]="tab1" class="tab1"  tabTitle="SO" &gt;&lt;/ion-tab&gt;
              &lt;ion-tab [root]="tab2"  class="tab2"  tabTitle="PO" &gt;&lt;/ion-tab&gt;
          &lt;/ion-tabs&gt;`,
  
  })
  </code></pre>
  
  <p>i tried in e2e as:</p>
  
  <pre><code>describe('Approval Module', () =&gt; {
      it('Should click on the SO tab',() =&gt; {
          element(by.css(tab1)).click();
          browser.driver.sleep(6000); 
      });
  });
  </code></pre>
  
  <p>but i got an err like</p>
  
  <pre><code>approval.e2e.ts (3,18): Cannot find name 'tab1'. (2304)
  </code></pre>
  
  <p>could some one help me to click that tab</p>