I guess, although honestly, the test seems not to really be checking A/W conversion, so maybe it'd make more sense to sidestep it by just changing the test to use W functions instead?
[Also, the test is quite awful in a lot of ways, like checking multiple things at once in an ok() message, not printing the expected or received values, using ok (0) inside a conditional, using magic numbers, and perhaps most confusingly, I can't even tell what it's trying to test. That DceErrorInqText() matches FormatMessage()? If so, why does it never test that real messages match...]