Reason: Sometimes we need to add a temp test code but forget to disable it in the release ( production ) version.
Wrap it to DEBUG scope will keep the release code clean & safe.
Example:
#if DEBUG
// set purchased to ture in debug mode
// but we really don't want that we forget to mark it in release, it's dangerous.
storeManage.isPurchased = true
#endif
So, anyway please make sure your test code is for DEBUG mode only.