Test system for the Widl compiler

[Bernhard Kölbl]

Hey everyone,

during the course of implementing WinRT / UWP stuff, I regularly come
across missing IDL 3.0 features in our Widl compiler.
Unfortunately, Widl's code seems to have grown in a rater unpleasant
direction and is sometimes a real burden to understand and maintain. I
think some refactoring to its code would be very well fitting and make
things a lot easier for everyone, but refactoring can also bring
breakage and makes tracking down errors with Git harder. Additionally,
as the code is already not that small, errors have an easy way to slip
in without noticing.
So to me, the ideal solution seems to add a testing system to the
compiler, like most of Wine's components already have.

Rémi and I already outlined some ideas:
- Port the Winetest system to Unix programs
- Make a libwidl or Widl.exe and test against that with our current test system
- Add the tests into Widl itself as callable parameter

What do you think is the best solution?
Getting some suggestions would be great. :)

Thanks,
Bernhard