Angular Call

HTML

<div ng-app="myApp">
<div ng-controller="myCtrl">
   <p>{{testName}}</p>
</div>
</div>

JavaScript

angular.module('myApp',[])
   .controller("myCtrl",["$scope","$interval",function($scope, $interval){
        $scope.tests = [{
            "testName" : "Test-1 : Windows Test"
    		}, 
            {
            "testName" : "Test-2 : Linux Test"
    		},          
            {
            "testName" : "Test-3 : Unix Test"
    		} 
    	];
         var count=0;                    
         $interval(function(){                         
                $scope.testName=$scope.tests[count].testName;
                 count=count+1;
                if($scope.tests.length==count){
                  count=0;
                }                               
         },1000);   // I don't know it's exact 30 seconds     
    }]);