Generally we make a copy of the data into a test library
The library list that is in effect when the program is run usually (except for overrides ) determines which library(s) are used.
Testing can be done using the interactive debugger: STRDBG (F4 to prompt the display)
identify the program. You will notice that it contains the option
Update production files . . . . *NO
With no set the debugger will not change values in any library of type PROD.
Infact this option will abort when your program trys to open anyfile for update or output in a library of type PROD.
If you are using InforZA you can just create another environment specifically for testing. We do this using the PowerLink GUI.