Unit testing effectively - Logic example (Part I)

MyBusinessLogic.php

<?php declare(strict_types=1);

namespace Company\Domain;

final class MyBusinessLogic
{
    private DependencyInterface $dependencyInterface;
    private ConcreteDependency $concrete;

    public function __construct(
        DependencyInterface $dependencyInterface,
        ConcreteDependency $concrete
    ) {
        $this->dependencyInterface = $dependencyInterface;
        $this->concrete = $concrete;
    }

    public function applySomeLogic(Input $input): ReturnType
    {
        // black box responsible to create a ReturnType
        // based on the given Input
        return $returnType;
    }
}