<?php

use \PHPUnit\Framework\MockObject\Stub;

interface SomeInterface
{
    public function execute(): string;
}

final class FoobarTest extends \PHPUnit\Framework\TestCase
{
    private SomeInterface&Stub $service;
    
    protected function setUp() {
        $this->service = $this->createStub(SomeInterface::class);
    }
    
    public function run(bool $param)
    {
        $this->service->method('execute')->willReturnMap(['asdf', 'adsfasdf']);
        
        $this->service->execute(); // simulate test
    }
}