Hi Amit,
Pre and post archiving tests should be done on the data that is getting archived.I mean how that data displayed in the live system and how is it getting displayed from archive.
You need to know if any standard reports or custom reports are fetching the data above the residence time you have configured in the system. If so, you need to alter them. I am sure standard report wouldn't get affected as few reports in FI, SD, MM are archive enabled. they are capable enough in fetching archived data as well.
Thanks,
Bala.