To set the default action from index to any other you want to override property of the class $defaultAction. Example of set the default action with the index on the test:
<?php
class MyTestController extends Controller {
/**
* Default action
*
* @var string
*/
public $defaultAction = 'test';
public function actionTest() {
//your code
}
}
After you specify a property of the class $defaultAction application will apply to the test method for the url: index.php?r=myTest or if the included friendly url: /myTest