PHPUnit's MemoryGuard

MemoryGuard.php

<?php

declare(strict_types=1);

namespace Answear\DevelopmentHelpers\PHPUnit;

use PHPUnit\Framework\Test;
use PHPUnit\Framework\TestListener;
use PHPUnit\Framework\TestListenerDefaultImplementation;

class MemoryGuard implements TestListener
{
    use TestListenerDefaultImplementation;

    private const PHPUNIT_PROPERTY_PREFIX = 'PHPUnit';

    /**
     * @var callable
     */
    private $unsetter;

    public function __construct()
    {
        $this->unsetter = function ($propertyName) {
            unset($this->$propertyName);
        };
    }

    public function endTest(Test $test, float $time): void
    {
        $this->safelyFreeProperties($test);
    }

    private function safelyFreeProperties(Test $test): void
    {
        $testReflection = new \ReflectionObject($test);

        foreach ($this->getAllProperties($testReflection) as $property) {
            $this->unsetter = $this->unsetter->bindTo($test, $property->getDeclaringClass()->getName());
            if ($this->isSafeToFreeProperty($property)) {
                ($this->unsetter)($property->getName());
            }
        }
    }

    private function isSafeToFreeProperty(\ReflectionProperty $property): bool
    {
        return !$property->isStatic() && $this->isNotPhpUnitProperty($property);
    }

    private function isNotPhpUnitProperty(\ReflectionProperty $property): bool
    {
        return 0 !== strpos($property->getDeclaringClass()->getName(), self::PHPUNIT_PROPERTY_PREFIX);
    }

    /**
     * @return \ReflectionProperty[]
     */
    private function getAllProperties(\ReflectionObject $object): array
    {
        $properties = $object->getProperties();
        while ($object->getParentClass()) {
            $object = $object->getParentClass();
            if (0 === strpos($object->getNamespaceName(), self::PHPUNIT_PROPERTY_PREFIX)) {
                break;
            }
            $properties = array_merge($properties, $object->getProperties(\ReflectionProperty::IS_PRIVATE));
        }

        return $properties;
    }
}