php - I install Laravel on window 7 and I got error message -

i install laravel when run demo file gave me error message. error message that:-

     class 'illuminate\foundation\testing\testcase' not found in d:\xampp\htdocs\laravel\tests\testcase.php on line 4 

for solving issues tried run phpunit app/tests/ command on command prompt nothing happend. , composer.json file :--

  {    "name": "laravel/laravel",    "description": "the laravel framework.",    "keywords": ["framework", "laravel"],    "license": "mit",    "type": "project",    "require": {     "php": ">=5.5.9",     "laravel/framework": "5.2.*"   }, "require-dev": {     "fzaninotto/faker": "~1.4",     "mockery/mockery": "0.9.*",     "phpunit/phpunit": "~4.0",     "symfony/css-selector": "2.8.*|3.0.*",     "symfony/dom-crawler": "2.8.*|3.0.*" }, "autoload": {     "classmap": [         "database"     ],     "psr-4": {         "app\\": "app/"     } }, "autoload-dev": {     "classmap": [         "tests/testcase.php"     ] }, "scripts": {     "post-root-package-install": [         "php -r \"copy('.env.example', '.env');\""     ],     "post-create-project-cmd": [         "php artisan key:generate"     ],     "post-install-cmd": [         "illuminate\\foundation\\composerscripts::postinstall",         "php artisan optimize"     ],     "post-update-cmd": [         "illuminate\\foundation\\composerscripts::postupdate",         "php artisan optimize"     ] }, "config": {     "preferred-install": "dist" } 

}

have got tests folder in laravel project root? , have testcase.php inside of that?