Error: Cannot instantiate interface symfony when unit testing

Question

I'm trying to do a unit test for a signup method and im following this guide. I'm fairly new to unit testing.

i keep getting

1) App\Tests\Controller\SignUpControllerTest::testSignUp Error: Cannot instantiate interface Symfony\Component\Security\Core\Encoder\UserPasswordEncoderInterface

/Applications/MAMP/htdocs/my_project/tests/Controller/SignUpControllerTest.php:19

I just don't think im doing this unit test right. Here is what i have. I'm not sure on what im doing. All i want to do is test the signup method.

UserController.php

public function signup(Request $request, UserPasswordEncoderInterface $passwordEncoder )
{
    $user = new User();

    $entityManager = $this->getDoctrine()->getManager();

    $user->setEmail($request->get('email'));
    $user->setPlainPassword($request->get('password'));
    $user->setUsername($request->get('username'));
    $password = $passwordEncoder->encodePassword($user, $user->getPlainPassword());
    $user->setPassword($password);

    $entityManager->persist($user);
    $entityManager->flush();

    return $this->redirectToRoute('login');



}

SignUpControllerTest.php

namespace App\Tests\Controller;

use App\Entity\Product;
use App\Controller\UserController;
use App\Entity\User;
use Doctrine\Common\Persistence\ObjectManager;
use Doctrine\Common\Persistence\ObjectRepository;
use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
use Symfony\Component\Security\Core\Encoder\UserPasswordEncoderInterface;
use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

class SignUpControllerTest extends WebTestCase
{

    public function testSignUp()
    {   
        $passwordEncoder = new UserPasswordEncoderInterface();
        $user = new User();
        $user->setEmail('janedoe123@aol.com');
        $user->setPlainPassword('owlhunter');
        $user->setUsername('BarnMan');
        $password = $passwordEncoder->encodePassword($user, $user->getPlainPassword());
        $user->setPassword($password);

        $userRepository = $this->createMock(ObjectRepository::class);
        $userRepository->expects($this->any())
            ->method('find')
            ->willReturn($user);


        $objectManager = $this->createMock(ObjectManager::class);
        // use getMock() on PHPUnit 5.3 or below
        // $objectManager = $this->getMock(ObjectManager::class);
        $objectManager->expects($this->any())
            ->method('getRepository')
            ->willReturn($userRepository);

        $userController = new UserController($objectManager);
        $this->assertEquals(2100, $userController->signupTest());

    }


}

Matías Navarro Carter Matías Navarro Carter · Accepted Answer · 2018-08-25T04:50:25

The error is very clear. In the first line of your testSignUp method, you are creating an instance out of an interface, which cannot be done in PHP.

To create a usable object out of an interface in unit testing, create a mock object of it. Read PHP unit docs for that.

Error: Cannot instantiate interface symfony when unit testing

1 Answers