IDOC regression testing

Hi! all..

We would like to do regression testing on an IDOC that was modified a bit.

Modification in the sense, we added some code to pass the DUNS # from a custom table to LIFNR field of the IDOC. I see no regression with this. But my ABAPer is very adamant that I do regession.

For such a scenario, what wud be the ideal procedure to do it?

please help me out.

thanks a lot.

-sri.