The effect of testing is to:

Testing provides valuable information about the quality of the software by identifying defects and issues before the software is released. It helps stakeholders make informed decisions about the release and deployment of the software. While testing can identify defects and provide confidence in the quality of the software, it cannot guarantee the absence of defects or ensure that thesoftware quality will inherently increase. The primary goal of testing is to reveal problems and provide an indication of the software's current state of quality.