What types of testing do you know that are used when making changes to code or systems?

Main types of testing when making changes to code or system:

• Unit Testing — testing individual functions or classes.
• Integration Testing — testing the interaction between modules.
• Regression Testing — ensuring that changes do not break existing functionality.
• Functional Testing — verifying that the functionality meets requirements.
• System Testing — testing the entire system as a whole.
• Acceptance Testing — testing the system from the user's perspective.
• Performance Testing — testing speed and stability.
• Security Testing — testing for vulnerabilities.

The choice depends on the type of changes and testing goals.