laravel/app/tests/TestCase.php

<?php

class TestCase extends Illuminate\Foundation\Testing\TestCase {

    /**
     * Creates the application.
     *
     * @return Symfony\Component\HttpKernel\HttpKernelInterface
     */
    public function createApplication()
    {
    	$unitTesting = true;

        $testEnvironment = 'testing';

    	return require __DIR__.'/../../bootstrap/start.php';
    }

}