Seems like the permissions in /vendor/bin/phpunit are not correct, the phpunit file is not executable.
I suggest changing the permissions by running the following from inside the vendor folder:
chmod 766 bin -R
This should give the owner which is the vagrant user execute permissions.
WARNING: I did this myself and I am now getting the following error from phpunit when running gulp
Error: Command failed: You need to set up the project dependencies using the following commands: wget http://getcomposer.org/composer.phar php composer.phar install
I created my project with the laravel installer by running --> laravel new [project] .
Looks like it does not set the permissions correctly when you do this. So the solution is to install laravel using composer.
composer create-project laravel/laravel.
But if you want to avoid doing a fresh install you can do the following: