How to mock an exception

ThrowerChecker.php

<?php

use Symfony\Component\Security\Core\Exception\AccessDeniedException;
use Symfony\Component\Security\Http\Firewall\AccessListener;

class ThrowerChecker
{
    public function isThrownByFirewall(AccessDeniedException $exception): bool
    {
        // Walking through the stack frames and returning true if one of them is triggered by a specific class
        foreach ($exception->getTrace() as $stackItem) {
            $class = $stackItem['class'] ?? null;
            if ($class === AccessListener::class) {
                return true;
            }
        }

        return false;
    }
}

ThrowerCheckerTest.php

<?php

use PHPUnit\Framework\TestCase;
use Symfony\Component\Security\Core\Exception\AccessDeniedException;
use Symfony\Component\Security\Http\Firewall\AccessListener;

class ThrowerCheckerTest extends TestCase
{
    public function testIfExceptionsThrownByFirewallAreDetected(): void
    {
        $exception = new AccessDeniedException;
        self::overrideExceptionTrace(
            $exception,
            [['class' => 'foo'],
            ['class' => AccessListener::class], ['class' => 'bar']]
        );
        
        
    }
    
    /**
     * Overrides an exception trace through reflection, since this cannot be done through mocking (getTrace is final).
     *
     * @param array<int, array<string, mixed>> $trace
     */
    private static function overrideExceptionTrace(\Exception $exception, array $trace): void
    {
        $exceptionReflection = new \ReflectionObject($exception);

        // Find the parent root to be able to read the "trace" property because it's defined on the \Exception class
        while ($exceptionReflection->getParentClass() !== false) {
            $exceptionReflection = $exceptionReflection->getParentClass();
        }

        $traceReflection = $exceptionReflection->getProperty('trace');
        $traceReflection->setAccessible(true);
        $traceReflection->setValue($exception, $trace);
        $traceReflection->setAccessible(false);
    }
}