In , developers review the program code to find defects and suggest improvements.

In , developers walk through the program code manually to look for any potential issues.

Regression testing is performed to ensure that changes or fixes in the software do not introduce new .

In beta testing, the software is tested by a group of potential users in a environment.

System testing is performed on a complete, integrated system to evaluate the system's with its specified requirements.

3. testing is also known as structural testing or glass-box testing.