<?php

use PHPUnit\Framework\TestCase;

+#[\PHPUnit\Framework\Attributes\AllowMockObjectsWithoutExpectations]
final class FooTest extends TestCase
{
    private ClassToStub $foo;

    public function setUp(): void
    {
        parent::setUp();

        $foo = self::createStub(\ClassToStub::class);
        $foo->method('foo')->willReturn('error');

        $this->foo = $foo;
    }

    public function test()
    {
       $this->foo->foo();
    }
}

class ClassToStub
{
    public function foo(): string
    {
        return 'error';
    }
};