Where is 'Start Test' button in Sitecore Experience Editor

I am following this link Create an A/B or multivariate test in the Experience Editor which mentions about Testing tab as below to start testing and deploy the test variation.

In the Experience Editor, navigate to the page where you have created a test and then, on the Testing tab, in the Actions group, click Start Test.

But I am not getting the 'Start test' button anywhere or 'Testing' tab in Experience Editor. I have created Test Variations of Web Component that is setup with different data sources.

Since Testing tab is not visible I am not able to Start testing the web component.

Are there any prerequisites or something else I am missing ?

Sitecore version: 8.0 rev. 150223 (Analytics enabled)

Mongo Db version: 3.0.3