Setup Testing with Composer, Codeception, PHPUnit, AspectMock

_bootstrap.php

<?php

    $kernel = \AspectMock\Kernel::getInstance();

    $kernel->init([
        'debug'              => TRUE,

        // root of the app
        'appDir'             => __DIR__ . '/..',

        // cached php files
        'cacheDir'           => __DIR__ . '/_data/cache',

        // apply aspect on files in these directories
        'includePaths'       => [
            __DIR__ . '/../app',
            __DIR__ . '/../vendor',
        ],

        // exclude aspect (e.g. test files)
        'excludePaths'       => [
            __DIR__,
        ],

        // intercept global functions e.g. time()
        'interceptFunctions' => TRUE,
    ]);

UserServiceTest.php

<?php

    # we are in: /tests/Test

    namespace Test;

    use App\User;
    use App\UserService;
    use AspectMock\Test;

    class UserServiceTest extends \PHPUnit_Framework_TestCase
    {
        protected function _after()
        {
            // remove all registered test doubles
            Test::clean();
        }

        public function testCreateUserByName()
        {
            // create class proxy
            $user = Test::double('App\User', ['save' => FALSE]);

            /**
             * App\User instance will be created here
             * Calls: setName($name), save()
             * Normally save() returns TRUE
             * 
             * @return save() // returns FALSE since we overridden it
             */
            $response = (new UserService())->createUserByName('tino');

            // class proxy lets us know if this happened
            $user->verifyInvoked('save');
            
            // should succeed
            $this->assertFalse($response);
        }
    }