WWI and anything what you need to look at to use WWI can be a fantastic solution; but sometimes in real life it can be a nightmare as well (in the last week i believe i had to made "notes" which need to use a booklet to write down all the findings).
Here I would like to present one such example.
We know that we can have e.g. a specification report symbol and/or a parameter report symbol as part of a WWI layout (and many other stuff as part of a WWI layout).
And we know that a WWI layout might change in time (e.g. legal demand changes etc.).
In most cases the same generation variant is used in relation to a WWI layout to generate a report (assumption: we look for "released/historic" WWI reports).
We know as well that all the WWI report symbols stuff is related to same "ABAP" part in the background.
And we know: WWI is using as an "editor" WinWord, so we have the many font etc. options etc.
So we have a complex environment to look at if we discusss WWI.
What can go wrong in WWI
Based on a current example still you can "stuck" in WWI part a little bit. Even if you use WWI for a long time and you know (or you believe you know) the full WWI story by heart... you can be wrong. this has happened now...
And this is the short story
1.) Generation variant was not changed
2.) No report symbol was added, no real WWI change was done
3.) "only" one function module (in reference to some "parameter symbol" was changed)
And now this was tested etc. Regarding tests: there are many options to execute the test; but this was the story:
Some released report was generated in Quality SAP system and the WWI report was checked e.g. by using CG54/CG50 so that all symbols are expanded.
Sometimes it is a good idea to compare the results in the Quality system with the "Prod" system; and we found a difference (regression testing etc.) which we could not explained.
Then it was checked: what is wrong here...as the "function module" (which was adjusted) having no different logic in Prod than in Qual.
By hazard.... we discussed this finding in the team and a very simple answer come up regarding the difference.
We used in prod system a "very old" report and compared the result with Qual System. We ignored a little bit, that the "report symbols" are not really the same (this was an assumption) and this was the explanation why this parameter symbol showed a different result (comparing "Prod" and "Qual").
Yes it is sometimes a good idea to compare "qual" and "prod" results (if WWI layout etc. was changed) but sometimes you must be SURE that you really talk about the same symbols to avoid pitfalls.
So keep in mind to potentially check e.g. ESTLS content (and many other tables etc you can look at) to be sure, that anything is correct and that you then can explain teh difference and anything is "ok"...
Finally: the test in Qual System passed the test with "ok". So now the users can test.
I hope that this "booklet" (refer above) will be always present on my laptop/client (with all the lessons learned).