It's all part of the QA process

According to British Standard 7925 -1: 

"Testing is supposed to demonstrate that the software does what it is supposed to do as well as demonstrating that software does not do what it is not supposed to do." 

It is worth noting that testing can only show the presence of faults, it cannot prove that the software is 100% correct and it cannot prove that there are no faults.   Risk will reduce if subsequent re-work and re-testing takes place.