In PHP image manipulation, how do I write integration tests?

resizeImage($image, 50, 50);

        // Assert: Check if the resized image dimensions are as expected
        $this->assertEquals(50, imagesx($resizedImage));
        $this->assertEquals(50, imagesy($resizedImage));

        // Clean up
        imagedestroy($image);
        imagedestroy($resizedImage);
    }

    private function resizeImage($image, $width, $height)
    {
        // This is a placeholder for the actual resizing logic
        $resizedImage = imagecreatetruecolor($width, $height);
        imagecopyresampled($resizedImage, $image, 0, 0, 0, 0, $width, $height, imagesx($image), imagesy($image));
        return $resizedImage;
    }
}