PhpStorm Laravel 4.2 Fatal error: Class 'TestCase' not found in

I get this error when running trying to run unit tests from PhpStorm:

Fatal error: Class 'TestCase' not found in C:\xampp\htdocs\etestproject\app\tests\ExampleTest.php on line 3

There was a similar posts here, here and here but they didn't really help me.

I can run:

phpunit app/tests/

from my project's root directory but not from PhpStorm

Additional info:

When i add 'Illuminate\Foundation\Testing\TestCase' to my app/confg/app.php and run composer update after that it doesn't pass and if i add/require "phpunit/phpunit" to my composer.json and rum my tests from PhpStorm they still give back the same error.