Fatal Error: Class 'ctestcase' Not Found

Hello guys I am beginner to Yii framework. Every thing is working good in basics, but extending the classes is not working

Here is the code to check DB connection

<?php
class DBConnect extends CTestCase
{
public function testConnection()
{
$this->assertTrue(true);
}
}

The error which I get is as below in attachment



Can any 1 plz tell me whats the problem?

I am using mysql 5.6

php, pear n phpunit is all working find

Help me guys plz