TestDisk is a powerful data recovery utility. It was primarily designed to help recover lost partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software, certain types of viruses or human error (such as accidentally erasing your Partition Table).
PhotoRec is safe to use, it will never attempt to write to the drive or memory support you are about to recover from. Recovered files are instead written in the directory from where you are running the PhotoRec program. Version 6.3 includes unspecified updates.