Unable to run phpunit to test laravel on Windows 10

I have laravel 5.1 installed on a windows 10 machine. Laravel 5.1 comes pre installed with phpunit

I can see that it exist in vendor\bin directory - both phpunit and phpunit.bat

When I run the phpunit command from from the root of my laravel project I get the following error:

phpunit Cannot run program "phpunit" (in directory "C:\wamp\www\laravel\myproject"): CreateProcess error=2, The system cannot find the file specified

I tried the following vendor/bin/phpunit and i get the following error:

vendor/bin/phpunit Cannot run program "C:\wamp\www\laravel\leavetracker-5.1\vendor\bin\phpunit" (in directory "C:\wamp\www\laravel\myproject"): CreateProcess error=193, %1 is not a valid Win32 application

I've attempted to add phpunit as a environment variable aswell but it still doesnt work:

C:\wamp\www\laravel\myproject\vendor\bin;

via Chebli Mohamed