PhpUnit Artisan:call explode expects parameter 2 to be string

I'm trying to test a Laravel 5.1 controller with PhpUnit, for that im creating a class inheriting from TestCase, and using DatabaseTransactions and WithoutMiddleware traits.

Within the class im implementing the setUpBeforeClass method which contains:

Artisan::call('migrate:refresh');

When i try to run the test I get the following error:

1) JugadoresControllerTest::test_Index_trae_arreglo_de_jugadores
ErrorException: explode() expects parameter 2 to be string, array given

/home/vagrant/.composer/vendor/illuminate/support/helpers.php:390
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Support/Arr.php:319
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Support/Collection.php:428
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Database/Query/Builder.php:1548
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Database/Migrations/DatabaseMigrationRepository.php:53
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Database/Migrations/Migrator.php:79
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Database/Console/Migrations/MigrateCommand.php:74
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Container/Container.php:503
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Console/Command.php:150
/home/vagrant/Code/marcadores/vendor/symfony/symfony/src/Symfony/Component/Console/Command/Command.php:259
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Console/Command.php:136
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Console/Application.php:62
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php:152
/home/vagrant/Code/marcadores/vendor/laravel/framework/src/Illuminate/Support/Facades/Facade.php:210
/home/vagrant/Code/marcadores/tests/unit/JugadoresControllerTest.php:34
/home/vagrant/Code/marcadores/tests/unit/JugadoresControllerTest.php:34
/home/vagrant/.composer/vendor/phpunit/phpunit/src/TextUI/Command.php:151
/home/vagrant/.composer/vendor/phpunit/phpunit/src/TextUI/Command.php:103

Hope anyone can helpme!

via Chebli Mohamed