I have found a workaround for this.
In your config/database.php bellow mysql add:
'mysql_testing' => [
'driver' => 'mysql',
'host' => env('TESTING_DB_HOST', 'localhost'),
'database' => env('TESTING_DB_DATABASE', 'forge'),
'username' => env('TESTING_DB_USERNAME', 'forge'),
'password' => env('TESTING_DB_PASSWORD', ''),
'charset' => 'utf8',
'collation' => 'utf8_unicode_ci',
'prefix' => '',
'strict' => false,
],
And now in your .env add the values for:
TESTING_DB_HOST=localhost
TESTING_DB_DATABASE=homestead_testing
TESTING_DB_USERNAME=homestead
TESTING_DB_PASSWORD=secret
Now you can run
php artisan migrate --database=mysql_testing
And it will migrate your testing database.