When software engineers add lines of code and test them, what is typically done after testing?

• A. They add lines of code and comment on them after they're done with testing
• B. They immediately delete the new lines
• C. They publish the code to production without review
• D. They rerun tests without any changes

Answer: (A)

After adding new code and testing it, you typically document what you changed by commenting on the new lines. These comments explain what the code does, why the change was needed, and any important details or edge cases to watch for. This helps teammates and future you understand the purpose of the addition without digging through tests or trial-and-error. It also makes code reviews smoother, since the reviewer can quickly grasp intent and rationale.

Deleting the new lines would discard work, publishing to production without review skips important checks, and rerunning tests without changes doesn’t provide new information or clarify intent.