PHPUnit

<?php

namespace App\Tests\Service;

use App\Repository\FirstRepository;
use App\Repository\SecondRepository;
use App\Service\AppManager;
use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;

class AppManagerTest extends KernelTestCase
{

    public function testFirst_Success()
    {
        static::bootKernel();

        $a = 2;
        $b = 3;

        $firstRepositoryMock = $this->createMock(FirstRepository::class);
        $firstRepositoryMock->expects($this->once())
            ->method('find')
            ->with($a, $b);

        $appService = new AppManager(
            $firstRepositoryMock,
            self::$container->get('App\Repository\SecondRepository'),
        );

        $this->assertSame(5, $appService->first($a, $b));
    }

    public function testSecond_Success()
    {
        static::bootKernel();

        $secondRepositoryMock = $this->createMock(SecondRepository::class);
        $secondRepositoryMock->expects($this->once())
            ->method('clear');

        $appService = new AppManager(
            self::$container->get('App\Repository\FirstRepository'),
            $secondRepositoryMock,
        );

        $this->assertNull($appService->second());
    }

}

?>

<?php

namespace App\Service;

use App\Repository\FirstRepository;
use App\Repository\SecondRepository;

class AppManager
{

    /** @var FirstRepository */
    protected $firstRepository;
    /** @var SecondRepository */
    protected $secondRepository;

    public function __construct(
        FirstRepository $firstRepository,
        SecondRepository $secondRepository
    ) {
        $this->firstRepository = $firstRepository;
        $this->secondRepository = $secondRepository;
    }

    public function first(int $a, int $b): int
    {
        $this->firstRepository->find($a, $b);

        return $a + $b;
    }

    public function second(): void
    {
        $this->secondRepository->clear();
    }

}

?>