Francois Gouget fgouget@free.fr writes:
And having a single test that can be used to test both A and W
reduces code duplication, which helps maintainability and reduces the amount of work we have to do.
...and makes sure that the W functions are never actually tested with Unicode input. It's not enough to simply pass converted ASCII strings to the W functions, we have to test with real Unicode to check for lossy W->A->W conversions, surrogate handling, non-spacing chars, etc. The functions *are* really different and have different testing requirements.