Laravel PHPUnit Fatal error: Class 'PHPUnit_Util_Configuration' not found

I am trying to start testing my Laravel 5.1 app using PHPUnitbut everytime I run phpunit in the cmd line I get the following error:

PHPUnit_Framework_Exception: Fatal error: Class 'PHPUnit_Util_Configuration' not found in C:\Users\ross\AppData\Local\Temp\PHPCD2E.tmp on line 347

Call Stack:
    0.0001     116952   1. {main}() -:0
    0.0011     266968   2. require_once('C:\Users\ross\AppData\Local\Temp\PHPCD2E.tmp') -:1

C:\xampp\php\pear\PHPUnit\TextUI\Command.php:176
C:\xampp\php\pear\PHPUnit\TextUI\Command.php:129

I have check my settings as far as I understand they are all pretty default as they come with Laravel. Does anyone have a clue as to why this is happening and how I can fix it? Thanks

via Chebli Mohamed